old_contents: /*
  	MIT License http://www.opensource.org/licenses/mit-license.php
  	Author Tobias Koppers @sokra
  */
  "use strict";
  class ChunkModuleIdRangePlugin {
  	constructor(options) {
  		this.options = options;
  	}
  	apply(compiler) {
  		let options = this.options;
  		compiler.plugin("compilation", (compilation) => {
  			compilation.plugin("module-ids", (modules) => {
  				let chunk = this.chunks.filter((chunk) => {
  					return chunk.name === options.name;
  				})[0];
  				if(!chunk) throw new Error("ChunkModuleIdRangePlugin: Chunk with name '" + options.name + "' was not found");
  				let currentId = options.start;
  				let chunkModules;
  				if(options.order) {
  					chunkModules = chunk.modules.slice();
  					switch(options.order) {
  						case "index":
  							chunkModules.sort((a, b) => {
  								return a.index - b.index;
  							});
  							break;
  						case "index2":
  							chunkModules.sort((a, b) => {
  								return a.index2 - b.index2;
  							});
  							break;
  						default:
  							throw new Error("ChunkModuleIdRangePlugin: unexpected value of order");
  					}
  
  				} else {
  					chunkModules = modules.filter((m) => {
  						return m.chunks.indexOf(chunk) >= 0;
  					});
  				}
  				console.log(chunkModules);
  				for(let i = 0; i < chunkModules.length; i++) {
  					let m = chunkModules[i];
  					if(m.id === null) {
  						m.id = currentId++;
  					}
  					if(options.end && currentId > options.end)
  						break;
  				}
  			});
  		});
  	}
  }
  module.exports = ChunkModuleIdRangePlugin;
  
new_contents: /*
  	MIT License http://www.opensource.org/licenses/mit-license.php
  	Author Tobias Koppers @sokra
  */
  "use strict";
  class ChunkModuleIdRangePlugin {
  	constructor(options) {
  		this.options = options;
  	}
  	apply(compiler) {
  		const options = this.options;
  		compiler.plugin("compilation", (compilation) => {
  			compilation.plugin("module-ids", (modules) => {
  				const chunk = this.chunks.filter((chunk) => {
  					return chunk.name === options.name;
  				})[0];
  				if(!chunk) throw new Error("ChunkModuleIdRangePlugin: Chunk with name '" + options.name + "' was not found");
  				let currentId = options.start;
  				let chunkModules;
  				if(options.order) {
  					chunkModules = chunk.modules.slice();
  					switch(options.order) {
  						case "index":
  							chunkModules.sort((a, b) => {
  								return a.index - b.index;
  							});
  							break;
  						case "index2":
  							chunkModules.sort((a, b) => {
  								return a.index2 - b.index2;
  							});
  							break;
  						default:
  							throw new Error("ChunkModuleIdRangePlugin: unexpected value of order");
  					}
  
  				} else {
  					chunkModules = modules.filter((m) => {
  						return m.chunks.indexOf(chunk) >= 0;
  					});
  				}
  				console.log(chunkModules);
  				for(let i = 0; i < chunkModules.length; i++) {
  					const m = chunkModules[i];
  					if(m.id === null) {
  						m.id = currentId++;
  					}
  					if(options.end && currentId > options.end)
  						break;
  				}
  			});
  		});
  	}
  }
  module.exports = ChunkModuleIdRangePlugin;
  
subject: use const where applicable in ChunkModuleIdRangePlugin