one webpack plugin create json file with template / 一个用于根据json模板文件生成json文件的webpack插件

gistfile1.txt

"use strict"
const fs = require('fs');
const path = require('path');

function MP(templateFile, options){
	let _this = this,
			mp = {};
	//获取webpack root
	let rootPath = path.dirname(module.parent.filename);
	let tmpFilePath = path.resolve(rootPath, templateFile);
	mp.tmpFilePath = tmpFilePath;
	if(fs.existsSync(templateFile)){
		mp.existTMPFile = true;
	}
	if(typeof options === "string"){
		//替换文件的路径
	 let settingFilePath = path.resolve(rootPath, options);
	 if(fs.existsSync(settingFilePath)){
    mp.replaceFile = settingFilePath;
	 }else{
		console.info('没有指定认识配置文件')
		mp.data = null;
	 }
	}else if(typeof options === 'object'){
		mp.data = options;
	}
	if(!mp.existTMPFile && !mpMP.data){
		throw '不能同时为空'
	}
	mp.temName = path.basename(tmpFilePath);
	this.mp = mp;
}

MP.prototype.apply = function(compiler){
	let _this = this,
			originData = {},
			destData = _this.mp.data,
			webpackOptions = compiler.options,
			output = webpackOptions.output.path;

		compiler.plugin('emit', function(compilation, callback){

      let watchedFiles = compilation.fileDependencies,
          replaceFile = _this.mp.replaceFile;
			if(_this.mp.existTMPFile){
				originData = JSON.parse(fs.readFileSync(_this.mp.tmpFilePath));
      }
      if(replaceFile){
        if(watchedFiles.includes(replaceFile)){
          Object.assign(originData, readJSON(replaceFile));
        }else{
          Object.assign(originData, readJSON(replaceFile));
          compilation.fileDependencies.push(replaceFile)
        }
      }else{
        Object.assign(originData, destData);
      }
			compilation.assets[_this.mp.temName] = {
				source: () => JSON.stringify(originData, null, 2),
				size: () => originData.length,
			};
      callback();
		})
}
function readJSON(file){
  return JSON.parse(fs.readFileSync(file, 'utf8'))
}
module.exports = MP;