three.js/examples/jsm/nodes/accessors/LightNode.js

import { TempNode } from '../core/TempNode.js';

function LightNode( scope ) {

	TempNode.call( this, 'v3', { shared: false } );

	this.scope = scope || LightNode.TOTAL;

}

LightNode.TOTAL = 'total';

LightNode.prototype = Object.create( TempNode.prototype );
LightNode.prototype.constructor = LightNode;
LightNode.prototype.nodeType = 'Light';

LightNode.prototype.generate = function ( builder, output ) {

	if ( builder.isCache( 'light' ) ) {

		return builder.format( 'reflectedLight.directDiffuse', this.type, output );

	} else {

		console.warn( 'THREE.LightNode is only compatible in "light" channel.' );

		return builder.format( 'vec3( 0.0 )', this.type, output );

	}

};

LightNode.prototype.copy = function ( source ) {

	TempNode.prototype.copy.call( this, source );

	this.scope = source.scope;

	return this;

};

LightNode.prototype.toJSON = function ( meta ) {

	var data = this.getJSONNode( meta );

	if ( ! data ) {

		data = this.createJSONNode( meta );

		data.scope = this.scope;

	}

	return data;

};

export { LightNode };