alias.js

const path = require("path");
const cssAliasses = require("css-aliases");

// js
const REQUIRE_REGEX = /require\(['"](.*?)['"]\)/g;
const JS_IMPORT_FROM = /from\s+['"](.*?)['"]/g;
const JS_IMPORT = /import\s+['"](.*?)['"]/g;
// wxml
const SRC_REGEX = /src=['"](.*?)['"]/g;
// json
const JSON_REGEX = /['"](.*?)['"]/g;


let keysPattern;
let opt;
let filePath;

function setKeysPatten(options) {
  options = options || {};
  keysPattern = keysPattern || new RegExp(`^(${Object.keys(options).join("|")})`);
}

function replaceCallback(match, subMatch) {
  if (keysPattern.test(subMatch)) {
    const indexEnd = subMatch.indexOf("/") === -1 ? subMatch.length : subMatch.indexOf("/");
    const key = subMatch.substring(0, indexEnd);
    if (!opt[key]) {
      return match;
    }
    const url = path.join(opt[key], subMatch.slice(indexEnd));
    return match.replace(
      subMatch,
      path
        .relative(filePath, url)
        .replace(/\\/g, "/")
        .replace(/^\.\.\//, "")
    );
  } else {
    return match;
  }
}

module.exports = function alias(options, content, _filePath) {
  opt = options = options || {};
  filePath = _filePath;
  setKeysPatten(options);
  switch (path.extname(_filePath)) {
    case ".js":
    case ".wxs":
    case ".ts":
      content = content.replace(JS_IMPORT_FROM, replaceCallback);
      content = content.replace(JS_IMPORT, replaceCallback);
      content = content.replace(REQUIRE_REGEX, replaceCallback);
      break;
    case ".wxml":
      content = content.replace(SRC_REGEX, replaceCallback);
      break;
    case ".json":
      content = content.replace(JSON_REGEX, replaceCallback);
      break;
    case ".styl":
    case ".stylus":
    case ".less":
    case ".sass":
    case ".scss":
    case ".css":
    case ".wxss":
      content = cssAliasses(content, _filePath, options);
      break;
    default:
      break;
  }
  return content;
};