three.js/examples/jsm/nodes/lighting/AmbientLightNode.js

import AnalyticLightNode from './AnalyticLightNode.js';
import { addLightNode } from './LightsNode.js';
import { addNodeClass } from '../core/Node.js';

import { AmbientLight } from 'three';

class AmbientLightNode extends AnalyticLightNode {

	constructor( light = null ) {

		super( light );

	}

	setup( { context } ) {

		context.irradiance.addAssign( this.colorNode );

	}

}

export default AmbientLightNode;

addNodeClass( 'AmbientLightNode', AmbientLightNode );

addLightNode( AmbientLight, AmbientLightNode );