less.convert.js

"use strict";

let fs = require('fs');
let pathUtil = require('path');
let less = require("less");

let genDistPath = pathUtil.join(__dirname, 'src', '__gen_components', 'release');
let genPath = pathUtil.join(__dirname, 'src', '__gen_components');
let lessFilePool = [];
let handledLessFileCount = 0;

let tsFileTester = /\.ts$/;
let stylesRegex = /styleUrls *:(\s*\[[^\]]*?\])/g;
let stringRegex = /(['"])((?:[^\\]\\\1|.)*?)\1/g;
let lessNumRegex = /style_(\d+)_less/g;

function getTsFile(path, parse) {
  try {
    if (fs.statSync(path).isFile() && tsFileTester.test(path)) {
      parse(path)
    } else if (fs.statSync(path).isDirectory() && path.indexOf(genDistPath) < 0) {
      // 单是一个文件夹且不是dist文件夹的情况下
      let paths = fs.readdirSync(path);
      paths.forEach(function (p) {
        getTsFile(pathUtil.join(path, p), parse);
      })
    }
  } catch (err) {
    throw err;
  }
}

function transformStyleUrls(path) {
  let content = fs.readFileSync(path);
  if (stylesRegex.test(content)) {
    let contentTemp = content.toString().replace(stylesRegex, function (match, urls) {
      return "styles:" + urls.replace(stringRegex, function (match, quote, url) {
        lessFilePool.push(pathUtil.resolve(pathUtil.dirname(path), url))
        let result = 'style_' + handledLessFileCount + '_less';
        handledLessFileCount += 1;
        return result;
      })
    })
    fs.writeFileSync(path, contentTemp);
  }
}

function doneOne() {
  handledLessFileCount += 1;
  // 说明所有处理完成。
  if (handledLessFileCount === lessFilePool.length) {
    writeBack();
  }
}

function writeBack() {
  console.log("start to write back");
  getTsFile(genPath, writeBackCss);
  console.log('Done');
}

function writeBackCss(path) {
  let content = fs.readFileSync(path);
  if (lessNumRegex.test(content)) {
    let contentTemp = content.toString().replace(lessNumRegex, function (match, index) {
      return '`' + lessFilePool[index] + '`';
    });
    fs.writeFileSync(path, contentTemp);
  }
}

function processLess() {
  let index = 0;
  while (index < lessFilePool.length) {
    (function (index) {
      // debugger
      fs.readFile(lessFilePool[index], function (e, data) {
        less.render(data.toString(), {
          filename: lessFilePool[index]
        }, function (e, output) {
          lessFilePool[index] = output.css.replace(/\\e/g, function (match, e) {
            // 对content中的类似'\e630'中的\e进行处理
            return '\\\\e';
          }).replace(/\\E/g, function (match, e) {
            // 对content中的类似'\E630'中的\E进行处理
            return '\\\\E';
          }).replace(/\\20/g, function (match, e) {
            // 对content中的类似'\20'中的\20进行处理
            return '\\\\20';
          }).replace(/`/g, function (match, e) {
            // 处理css中`符号
            return "'";
          });
          doneOne();
        })
      })
    })(index);
    index += 1
  }
}

function process() {
  // 把所有ts文件，引入的less文件的完整路径放到全局list里面, 并且对源文件进行占坑
  getTsFile(genPath, transformStyleUrls);
  // 重置文件处理进度的计数器
  handledLessFileCount = 0;
  // 对list里面的每一个less文件进行翻译并触发css回写
  console.log("start to translate from less 2 css");
  processLess();
}

console.log('prepare...');
// 转换操作
process();