three.js/examples/jsm/nodes/procedural/CheckerNode.js

import TempNode from '../core/TempNode.js';
import { uv } from '../accessors/UVNode.js';
import { addNodeClass } from '../core/Node.js';
import { addNodeElement, tslFn, nodeProxy } from '../shadernode/ShaderNode.js';

const checkerShaderNode = tslFn( ( inputs ) => {

	const uv = inputs.uv.mul( 2.0 );

	const cx = uv.x.floor();
	const cy = uv.y.floor();
	const result = cx.add( cy ).mod( 2.0 );

	return result.sign();

} );

class CheckerNode extends TempNode {

	constructor( uvNode = uv() ) {

		super( 'float' );

		this.uvNode = uvNode;

	}

	setup() {

		return checkerShaderNode( { uv: this.uvNode } );

	}

}

export default CheckerNode;

export const checker = nodeProxy( CheckerNode );

addNodeElement( 'checker', checker );

addNodeClass( 'CheckerNode', CheckerNode );