diff --git a/lib/node_modules/@stdlib/plot/vega/transform/loess/examples/index.js b/lib/node_modules/@stdlib/plot/vega/transform/loess/examples/index.js
new file mode 100644
index 000000000000..65c5dfd7a4f0
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/loess/examples/index.js
@@ -0,0 +1,30 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+var Field = require( '@stdlib/plot/vega/field/ctor' );
+var LoessTransform = require( './../lib' );
+
+var transform = new LoessTransform({
+	'x': new Field({ 'field': 'dv' }),
+	'y': new Field({ 'field': 'iv' }),
+	'bandwidth': 0.2
+});
+
+console.log( transform.toJSON() );
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/as/get.js b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/as/get.js
new file mode 100644
index 000000000000..7932e5a40214
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/as/get.js
@@ -0,0 +1,43 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+/* eslint-disable no-invalid-this */
+
+'use strict';
+
+// MODULES //
+
+var prop = require( './properties.js' );
+
+
+// MAIN //
+
+/**
+* Returns the output field names for the predictor and predicted values.
+*
+* @private
+* @returns {(string|void)} output field names
+*/
+function get() {
+	return this[ prop.private ];
+}
+
+
+// EXPORTS //
+
+module.exports = get;
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/as/properties.js b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/as/properties.js
new file mode 100644
index 000000000000..3f2304dc2f08
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/as/properties.js
@@ -0,0 +1,33 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+// MODULES //
+
+var property2object = require( '@stdlib/plot/vega/base/property2object' );
+
+
+// MAIN //
+
+var obj = property2object( 'as' );
+
+
+// EXPORTS //
+
+module.exports = obj;
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/as/set.js b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/as/set.js
new file mode 100644
index 000000000000..3866f5fd788c
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/as/set.js
@@ -0,0 +1,66 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+/* eslint-disable no-invalid-this */
+
+'use strict';
+
+// MODULES //
+
+var logger = require( 'debug' );
+var isString = require( '@stdlib/assert/is-string' ).isPrimitive;
+var isUndefined = require( '@stdlib/assert/is-undefined' );
+var format = require( '@stdlib/string/format' );
+var changeEvent = require( './../change_event.js' );
+var prop = require( './properties.js' );
+
+
+// VARIABLES //
+
+var debug = logger( 'vega:loess-transform:set:'+prop.name );
+
+
+// MAIN //
+
+/**
+* Sets the output field names for the predictor and predicted values.
+*
+* ## Notes
+*
+* -   Providing `undefined` "unsets" the configured value.
+*
+* @private
+* @param {(string|void)} value - input value
+* @throws {TypeError} must be a string
+* @returns {void}
+*/
+function set( value ) {
+	if ( !isString( value ) && !isUndefined( value ) ) {
+		throw new TypeError( format( 'invalid assignment. `%s` must be a string. Value: `%s`.', prop.name, value ) );
+	}
+	if ( value !== this[ prop.private ] ) {
+		debug( 'Current value: %s. New value: %s.', this[ prop.private ], value );
+		this[ prop.private ] = value;
+		this.emit( 'change', changeEvent( prop.name ) );
+	}
+}
+
+
+// EXPORTS //
+
+module.exports = set;
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/bandwidth/get.js b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/bandwidth/get.js
new file mode 100644
index 000000000000..247bb9d5e1b7
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/bandwidth/get.js
@@ -0,0 +1,43 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+/* eslint-disable no-invalid-this */
+
+'use strict';
+
+// MODULES //
+
+var prop = require( './properties.js' );
+
+
+// MAIN //
+
+/**
+* Returns the smoothing parameter.
+*
+* @private
+* @returns {number} bandwidth
+*/
+function get() {
+	return this[ prop.private ];
+}
+
+
+// EXPORTS //
+
+module.exports = get;
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/bandwidth/properties.js b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/bandwidth/properties.js
new file mode 100644
index 000000000000..df1f857e3f75
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/bandwidth/properties.js
@@ -0,0 +1,33 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+// MODULES //
+
+var property2object = require( '@stdlib/plot/vega/base/property2object' );
+
+
+// MAIN //
+
+var obj = property2object( 'bandwidth' );
+
+
+// EXPORTS //
+
+module.exports = obj;
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/bandwidth/set.js b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/bandwidth/set.js
new file mode 100644
index 000000000000..3cb114c52c48
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/bandwidth/set.js
@@ -0,0 +1,61 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+/* eslint-disable no-invalid-this */
+
+'use strict';
+
+// MODULES //
+
+var logger = require( 'debug' );
+var isNonNegativeNumber = require( '@stdlib/assert/is-nonnegative-number' ).isPrimitive;
+var format = require( '@stdlib/string/format' );
+var changeEvent = require( './../change_event.js' );
+var prop = require( './properties.js' );
+
+
+// VARIABLES //
+
+var debug = logger( 'vega:loess-transform:set:'+prop.name );
+
+
+// MAIN //
+
+/**
+* Sets the smoothing parameter.
+*
+* @private
+* @param {NonNegativeNumber} value - input value
+* @throws {TypeError} must be a nonnegative number
+* @returns {void}
+*/
+function set( value ) {
+	if ( !isNonNegativeNumber( value ) ) {
+		throw new TypeError( format( 'invalid assignment. `%s` must be a nonnegative number. Value: `%s`.', prop.name, value ) );
+	}
+	if ( value !== this[ prop.private ] ) {
+		debug( 'Current value: %s. New value: %s.', this[ prop.private ], value );
+		this[ prop.private ] = value;
+		this.emit( 'change', changeEvent( prop.name ) );
+	}
+}
+
+
+// EXPORTS //
+
+module.exports = set;
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/change_event.js b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/change_event.js
new file mode 100644
index 000000000000..e444f9c667b0
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/change_event.js
@@ -0,0 +1,41 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+// MAIN //
+
+/**
+* Returns a new change event object.
+*
+* @private
+* @param {string} property - property name
+* @returns {Object} event object
+*/
+function event( property ) { // eslint-disable-line stdlib/no-redeclare
+	return {
+		'type': 'update',
+		'source': 'transform',
+		'property': property
+	};
+}
+
+
+// EXPORTS //
+
+module.exports = event;
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/defaults.js b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/defaults.js
new file mode 100644
index 000000000000..a519573f54e8
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/defaults.js
@@ -0,0 +1,43 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+// MAIN //
+
+/**
+* Returns defaults.
+*
+* @private
+* @returns {Object} default options
+*
+* @example
+* var o = defaults();
+* // returns {...}
+*/
+function defaults() {
+	return {
+		// The smoothing parameter:
+		'bandwidth': 0.3
+	};
+}
+
+
+// EXPORTS //
+
+module.exports = defaults;
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/groupby/get.js b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/groupby/get.js
new file mode 100644
index 000000000000..b5bacad05361
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/groupby/get.js
@@ -0,0 +1,43 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+/* eslint-disable no-invalid-this */
+
+'use strict';
+
+// MODULES //
+
+var prop = require( './properties.js' );
+
+
+// MAIN //
+
+/**
+* Returns the data fields to group by.
+*
+* @private
+* @returns {(Array<Field>|void)} fields
+*/
+function get() {
+	return this[ prop.private ];
+}
+
+
+// EXPORTS //
+
+module.exports = get;
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/groupby/properties.js b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/groupby/properties.js
new file mode 100644
index 000000000000..9132e7e77a3a
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/groupby/properties.js
@@ -0,0 +1,33 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+// MODULES //
+
+var property2object = require( '@stdlib/plot/vega/base/property2object' );
+
+
+// MAIN //
+
+var obj = property2object( 'groupby' );
+
+
+// EXPORTS //
+
+module.exports = obj;
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/groupby/set.js b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/groupby/set.js
new file mode 100644
index 000000000000..0ce83474460a
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/groupby/set.js
@@ -0,0 +1,84 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+/* eslint-disable no-invalid-this */
+
+'use strict';
+
+// MODULES //
+
+var logger = require( 'debug' );
+var isFieldArray = require( '@stdlib/plot/vega/base/assert/is-field-array' );
+var isUndefined = require( '@stdlib/assert/is-undefined' );
+var hasEqualValues = require( '@stdlib/array/base/assert/has-equal-values' );
+var copy = require( '@stdlib/array/base/copy' );
+var format = require( '@stdlib/string/format' );
+var changeEvent = require( './../change_event.js' );
+var prop = require( './properties.js' );
+
+
+// VARIABLES //
+
+var debug = logger( 'vega:loess-transform:set:'+prop.name );
+
+
+// MAIN //
+
+/**
+* Sets the data fields to group by.
+*
+* ## Notes
+*
+* -   Providing `undefined` "unsets" the configured value.
+*
+* @private
+* @param {(FieldArray|void)} value - input value
+* @throws {TypeError} must be an array of valid fields
+* @returns {void}
+*/
+function set( value ) {
+	if ( !isFieldArray( value ) ) {
+		if ( isUndefined( value ) ) {
+			if ( value === this[ prop.private ] ) {
+				return;
+			}
+			debug( 'Current value: %s. New value: %s.', JSON.stringify( this[ prop.private ] ), value );
+			this[ prop.private ] = value;
+			this.emit( 'change', changeEvent( prop.name ) );
+			return;
+		}
+		throw new TypeError( format( 'invalid assignment. `%s` must be an array of valid fields. Value: `%s`.', prop.name, value ) );
+	}
+	value = copy( value );
+	if ( isUndefined( this[ prop.private ] ) ) {
+		debug( 'Current value: %s. New value: %s.', this[ prop.private ], JSON.stringify( value ) );
+		this[ prop.private ] = value;
+		this.emit( 'change', changeEvent( prop.name ) );
+		return;
+	}
+	if ( !hasEqualValues( value, this[ prop.private ] ) ) {
+		debug( 'Current value: %s. New value: %s.', JSON.stringify( this[ prop.private ] ), JSON.stringify( value ) );
+		this[ prop.private ] = copy( value );
+		this.emit( 'change', changeEvent( prop.name ) );
+	}
+}
+
+
+// EXPORTS //
+
+module.exports = set;
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/index.js b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/index.js
new file mode 100644
index 000000000000..72535ffbeba2
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/index.js
@@ -0,0 +1,45 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+/**
+* Loess transform constructor.
+*
+* @module @stdlib/plot/vega/transform/loess
+*
+* @example
+* var Field = require( '@stdlib/plot/vega/field/ctor' );
+* var LoessTransform = require( '@stdlib/plot/vega/transform/loess' );
+*
+* var transform = new LoessTransform({
+*     'x': new Field({ 'field': 'dv' }),
+*     'y': new Field({ 'field': 'iv' }),
+*     'bandwidth': 0.2
+* });
+* // returns <LoessTransform>
+*/
+
+// MODULES //
+
+var main = require( './main.js' );
+
+
+// EXPORTS //
+
+module.exports = main;
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/main.js b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/main.js
new file mode 100644
index 000000000000..b88e0b0993ac
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/main.js
@@ -0,0 +1,313 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+/* eslint-disable no-restricted-syntax, no-invalid-this, stdlib/no-empty-lines-between-requires */
+
+'use strict';
+
+// MODULES //
+
+var EventEmitter = require( 'events' ).EventEmitter;
+var logger = require( 'debug' );
+var isObject = require( '@stdlib/assert/is-object' );
+var setNonEnumerableReadOnly = require( '@stdlib/utils/define-nonenumerable-read-only-property' );
+var setNonEnumerableReadOnlyAccessor = require( '@stdlib/utils/define-nonenumerable-read-only-accessor' ); // eslint-disable-line id-length
+var setReadWriteAccessor = require( '@stdlib/utils/define-read-write-accessor' );
+var hasProp = require( '@stdlib/assert/has-property' );
+var inherit = require( '@stdlib/utils/inherit' );
+var objectKeys = require( '@stdlib/utils/keys' );
+var instance2json = require( '@stdlib/plot/vega/base/to-json' );
+var transformErrorMessage = require( '@stdlib/plot/vega/base/transform-validation-message' );
+var format = require( '@stdlib/string/format' );
+var properties = require( './properties.json' );
+var defaults = require( './defaults.js' );
+
+// Note: keep the following in alphabetical order according to the `require` path...
+var getAs = require( './as/get.js' );
+var setAs = require( './as/set.js' );
+
+var getBandwidth = require( './bandwidth/get.js' );
+var setBandwidth = require( './bandwidth/set.js' );
+
+var getGroupby = require( './groupby/get.js' );
+var setGroupby = require( './groupby/set.js' );
+
+var getX = require( './x/get.js' );
+var setX = require( './x/set.js' );
+
+var getY = require( './y/get.js' );
+var setY = require( './y/set.js' );
+
+var getProperties = require( './properties/get.js' );
+
+
+// VARIABLES //
+
+var debug = logger( 'vega:loess-transform:main' );
+
+
+// MAIN //
+
+/**
+* Loess transform constructor.
+*
+* @constructor
+* @param {Options} options - constructor options
+* @param {Field} options.x - data field for the independent variable (predictor)
+* @param {Field} options.y - data field for the dependent variable (predicted)
+* @param {NonNegativeNumber} [options.bandwidth=0.3] - smoothing parameter
+* @param {(FieldArray|void)} [options.groupby] - data fields to group by
+* @param {string} [options.as] - output field names for the predictor and predicted values for the line of best fit
+* @throws {TypeError} options argument must be an object
+* @throws {Error} must provide valid options
+* @returns {LoessTransform} loess transform instance
+*
+* @example
+* var Field = require( '@stdlib/plot/vega/field/ctor' );
+*
+* var transform = new LoessTransform({
+*     'x': new Field({ 'field': 'dv' }),
+*     'y': new Field({ 'field': 'iv' }),
+*     'bandwidth': 0.2
+* });
+* // returns <LoessTransform>
+*/
+function LoessTransform( options ) {
+	var opts;
+	var keys;
+	var v;
+	var k;
+	var i;
+	if ( !( this instanceof LoessTransform ) ) {
+		return new LoessTransform( options );
+	}
+	EventEmitter.call( this );
+
+	if ( !isObject( options ) ) {
+		throw new TypeError( format( 'invalid argument. Options argument must be an object. Value: `%s`.', options ) );
+	}
+
+	// Check for required properties...
+	if ( !hasProp( options, 'x' ) ) {
+		throw new TypeError( 'invalid argument. Options argument must specify a data field for the independent variable.' );
+	}
+	if ( !hasProp( options, 'y' ) ) {
+		throw new TypeError( 'invalid argument. Options argument must specify a data field for the dependent variable.' );
+	}
+
+	// Resolve the default configuration:
+	opts = defaults();
+
+	// Set internal properties according to the default configuration...
+	keys = objectKeys( opts );
+	for ( i = 0; i < keys.length; i++ ) {
+		k = keys[ i ];
+		this[ '_'+k ] = opts[ k ];
+	}
+
+	// Validate provided options by attempting to assign option values to corresponding fields...
+	for ( i = 0; i < properties.length; i++ ) {
+		k = properties[ i ];
+		if ( !hasProp( options, k ) ) {
+			continue;
+		}
+		v = options[ k ];
+		try {
+			this[ k ] = v;
+		} catch ( err ) {
+			debug( 'Encountered an error. Error: %s', err.message );
+
+			// FIXME: retain thrown error type
+			throw new Error( transformErrorMessage( err.message ) );
+		}
+	}
+	return this;
+}
+
+/*
+* Inherit from the `EventEmitter` prototype.
+*/
+inherit( LoessTransform, EventEmitter );
+
+/**
+* Constructor name.
+*
+* @private
+* @name name
+* @memberof LoessTransform
+* @readonly
+* @type {string}
+*/
+setNonEnumerableReadOnly( LoessTransform, 'name', 'LoessTransform' );
+
+/**
+* Output field names for the predictor and predicted values for the line of best fit.
+*
+* @name as
+* @memberof LoessTransform.prototype
+* @type {string}
+*
+* @example
+* var Field = require( '@stdlib/plot/vega/field/ctor' );
+*
+* var transform = new LoessTransform({
+*     'x': new Field({ 'field': 'dv' }),
+*     'y': new Field({ 'field': 'iv' }),
+*     'as': 'predicted'
+* });
+*
+* var v = transform.as;
+* // returns 'predicted'
+*/
+setReadWriteAccessor( LoessTransform.prototype, 'as', getAs, setAs );
+
+/**
+* Smoothing parameter.
+*
+* @name bandwidth
+* @memberof LoessTransform.prototype
+* @type {NonNegativeNumber}
+* @default 0.3
+*
+* @example
+* var Field = require( '@stdlib/plot/vega/field/ctor' );
+*
+* var transform = new LoessTransform({
+*     'x': new Field({ 'field': 'dv' }),
+*     'y': new Field({ 'field': 'iv' }),
+*     'bandwidth': 0.2
+* });
+*
+* var v = transform.bandwidth;
+* // returns 0.2
+*/
+setReadWriteAccessor( LoessTransform.prototype, 'bandwidth', getBandwidth, setBandwidth );
+
+/**
+* Data fields to group by.
+*
+* @name groupby
+* @memberof LoessTransform.prototype
+* @type {(Array<Field>|void)}
+*
+* @example
+* var Field = require( '@stdlib/plot/vega/field/ctor' );
+*
+* var transform = new LoessTransform({
+*     'x': new Field({ 'field': 'dv' }),
+*     'y': new Field({ 'field': 'iv' }),
+*     'groupby': [ new Field({ 'field': 'category' }) ]
+* });
+*
+* var v = transform.groupby;
+* // returns [...]
+*/
+setReadWriteAccessor( LoessTransform.prototype, 'groupby', getGroupby, setGroupby );
+
+/**
+* Data field for the independent variable (predictor).
+*
+* @name x
+* @memberof LoessTransform.prototype
+* @type {Field}
+*
+* @example
+* var Field = require( '@stdlib/plot/vega/field/ctor' );
+*
+* var transform = new LoessTransform({
+*     'x': new Field({ 'field': 'dv' }),
+*     'y': new Field({ 'field': 'iv' })
+* });
+*
+* var v = transform.x;
+* // returns <Field>
+*/
+setReadWriteAccessor( LoessTransform.prototype, 'x', getX, setX );
+
+/**
+* Data field for the dependent variable (predicted).
+*
+* @name y
+* @memberof LoessTransform.prototype
+* @type {Field}
+*
+* @example
+* var Field = require( '@stdlib/plot/vega/field/ctor' );
+*
+* var transform = new LoessTransform({
+*     'x': new Field({ 'field': 'dv' }),
+*     'y': new Field({ 'field': 'iv' })
+* });
+*
+* var v = transform.y;
+* // returns <Field>
+*/
+setReadWriteAccessor( LoessTransform.prototype, 'y', getY, setY );
+
+/**
+* Loess transform properties.
+*
+* @name properties
+* @memberof LoessTransform.prototype
+* @type {Array<string>}
+*
+* @example
+* var Field = require( '@stdlib/plot/vega/field/ctor' );
+*
+* var transform = new LoessTransform({
+*     'x': new Field({ 'field': 'dv' }),
+*     'y': new Field({ 'field': 'iv' })
+* });
+*
+* var v = transform.properties;
+* // returns [...]
+*/
+setNonEnumerableReadOnlyAccessor( LoessTransform.prototype, 'properties', getProperties );
+
+/**
+* Serializes an instance to a JSON object.
+*
+* ## Notes
+*
+* -   This method is implicitly invoked by `JSON.stringify`.
+*
+* @name toJSON
+* @memberof LoessTransform.prototype
+* @type {Function}
+* @returns {Object} JSON object
+*
+* @example
+* var Field = require( '@stdlib/plot/vega/field/ctor' );
+*
+* var transform = new LoessTransform({
+*     'x': new Field({ 'field': 'dv' }),
+*     'y': new Field({ 'field': 'iv' }),
+*     'bandwidth': 0.2
+* });
+*
+* var v = transform.toJSON();
+* // returns {...}
+*/
+setNonEnumerableReadOnly( LoessTransform.prototype, 'toJSON', function toJSON() {
+	return instance2json( this, properties );
+});
+
+
+// EXPORTS //
+
+module.exports = LoessTransform;
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/properties.json b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/properties.json
new file mode 100644
index 000000000000..812660a77bd4
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/properties.json
@@ -0,0 +1,7 @@
+[
+  "as",
+  "bandwidth",
+  "groupby",
+  "x",
+  "y"
+]
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/properties/get.js b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/properties/get.js
new file mode 100644
index 000000000000..f3cbb28454ea
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/properties/get.js
@@ -0,0 +1,41 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+// MODULES //
+
+var properties = require( './../properties.json' );
+
+
+// MAIN //
+
+/**
+* Returns the list of enumerable properties.
+*
+* @private
+* @returns {Array<string>} properties
+*/
+function get() {
+	return properties.slice();
+}
+
+
+// EXPORTS //
+
+module.exports = get;
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/x/get.js b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/x/get.js
new file mode 100644
index 000000000000..04b95582992b
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/x/get.js
@@ -0,0 +1,44 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+/* eslint-disable no-invalid-this */
+
+'use strict';
+
+const Field = require('@stdlib/plot/vega/field/ctor/lib/main.js');
+// MODULES //
+
+var prop = require( './properties.js' );
+
+
+// MAIN //
+
+/**
+* Returns the data field for the independent variable.
+*
+* @private
+* @returns {Field} field
+*/
+function get() {
+	return this[ prop.private ];
+}
+
+
+// EXPORTS //
+
+module.exports = get;
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/x/properties.js b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/x/properties.js
new file mode 100644
index 000000000000..8562bbadefc2
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/x/properties.js
@@ -0,0 +1,33 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+// MODULES //
+
+var property2object = require( '@stdlib/plot/vega/base/property2object' );
+
+
+// MAIN //
+
+var obj = property2object( 'x' );
+
+
+// EXPORTS //
+
+module.exports = obj;
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/x/set.js b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/x/set.js
new file mode 100644
index 000000000000..dfcf85a0a184
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/x/set.js
@@ -0,0 +1,61 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+/* eslint-disable no-invalid-this */
+
+'use strict';
+
+// MODULES //
+
+var logger = require( 'debug' );
+var isField = require( '@stdlib/plot/vega/base/assert/is-field' );
+var format = require( '@stdlib/string/format' );
+var changeEvent = require( './../change_event.js' );
+var prop = require( './properties.js' );
+
+
+// VARIABLES //
+
+var debug = logger( 'vega:loess-transform:set:'+prop.name );
+
+
+// MAIN //
+
+/**
+* Sets the data field for the independent variable.
+*
+* @private
+* @param {Field} value - input value
+* @throws {TypeError} must be a valid field
+* @returns {void}
+*/
+function set( value ) {
+	if ( !isField( value ) ) {
+		throw new TypeError( format( 'invalid assignment. `%s` must be a valid field. Value: `%s`.', prop.name, value ) );
+	}
+	if ( value !== this[ prop.private ] ) {
+		debug( 'Current value: %s. New value: %s.', JSON.stringify( this[ prop.private ] ), JSON.stringify( value ) );
+		this[ prop.private ] = value;
+		this.emit( 'change', changeEvent( prop.name ) );
+	}
+}
+
+
+// EXPORTS //
+
+module.exports = set;
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/y/get.js b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/y/get.js
new file mode 100644
index 000000000000..a8e2e54360f0
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/y/get.js
@@ -0,0 +1,43 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+/* eslint-disable no-invalid-this */
+
+'use strict';
+
+// MODULES //
+
+var prop = require( './properties.js' );
+
+
+// MAIN //
+
+/**
+* Returns the data field for the dependent variable.
+*
+* @private
+* @returns {Field} field
+*/
+function get() {
+	return this[ prop.private ];
+}
+
+
+// EXPORTS //
+
+module.exports = get;
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/y/properties.js b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/y/properties.js
new file mode 100644
index 000000000000..3b4027c694ff
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/y/properties.js
@@ -0,0 +1,33 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+// MODULES //
+
+var property2object = require( '@stdlib/plot/vega/base/property2object' );
+
+
+// MAIN //
+
+var obj = property2object( 'y' );
+
+
+// EXPORTS //
+
+module.exports = obj;
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/y/set.js b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/y/set.js
new file mode 100644
index 000000000000..2eb9d669c04d
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/loess/lib/y/set.js
@@ -0,0 +1,61 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+/* eslint-disable no-invalid-this */
+
+'use strict';
+
+// MODULES //
+
+var logger = require( 'debug' );
+var isField = require( '@stdlib/plot/vega/base/assert/is-field' );
+var format = require( '@stdlib/string/format' );
+var changeEvent = require( './../change_event.js' );
+var prop = require( './properties.js' );
+
+
+// VARIABLES //
+
+var debug = logger( 'vega:loess-transform:set:'+prop.name );
+
+
+// MAIN //
+
+/**
+* Sets the data field for the dependent variable.
+*
+* @private
+* @param {Field} value - input value
+* @throws {TypeError} must be a valid field
+* @returns {void}
+*/
+function set( value ) {
+	if ( !isField( value ) ) {
+		throw new TypeError( format( 'invalid assignment. `%s` must be a valid field. Value: `%s`.', prop.name, value ) );
+	}
+	if ( value !== this[ prop.private ] ) {
+		debug( 'Current value: %s. New value: %s.', JSON.stringify( this[ prop.private ] ), JSON.stringify( value ) );
+		this[ prop.private ] = value;
+		this.emit( 'change', changeEvent( prop.name ) );
+	}
+}
+
+
+// EXPORTS //
+
+module.exports = set;
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/loess/package.json b/lib/node_modules/@stdlib/plot/vega/transform/loess/package.json
new file mode 100644
index 000000000000..791ce82b457d
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/loess/package.json
@@ -0,0 +1,61 @@
+{
+  "name": "@stdlib/plot/vega/transform/loess",
+  "version": "0.0.0",
+  "description": "Loess transform constructor.",
+  "license": "Apache-2.0",
+  "author": {
+    "name": "The Stdlib Authors",
+    "url": "https://github.com/stdlib-js/stdlib/graphs/contributors"
+  },
+  "contributors": [
+    {
+      "name": "The Stdlib Authors",
+      "url": "https://github.com/stdlib-js/stdlib/graphs/contributors"
+    }
+  ],
+  "main": "./lib",
+  "directories": {
+    "benchmark": "./benchmark",
+    "doc": "./docs",
+    "example": "./examples",
+    "lib": "./lib",
+    "test": "./test"
+  },
+  "types": "./docs/types",
+  "scripts": {},
+  "homepage": "https://github.com/stdlib-js/stdlib",
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/stdlib-js/stdlib.git"
+  },
+  "bugs": {
+    "url": "https://github.com/stdlib-js/stdlib/issues"
+  },
+  "dependencies": {},
+  "devDependencies": {},
+  "engines": {
+    "node": ">=0.10.0",
+    "npm": ">2.7.0"
+  },
+  "os": [
+    "aix",
+    "darwin",
+    "freebsd",
+    "linux",
+    "macos",
+    "openbsd",
+    "sunos",
+    "win32",
+    "windows"
+  ],
+  "keywords": [
+    "stdlib",
+    "plot",
+    "vega",
+    "transform",
+    "loess",
+    "constructor",
+    "ctor"
+  ],
+  "__stdlib__": {}
+}