parcel-bundler/lib/transforms/babel/jsx.js

Blazing fast, zero configuration web application bundler

"use strict";

var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault");

var _asyncToGenerator2 = _interopRequireDefault(require("@babel/runtime/helpers/asyncToGenerator"));

const path = require('path');

const JSX_EXTENSIONS = {
  '.jsx': true,
  '.tsx': true
};
const JSX_PRAGMA = {
  react: 'React.createElement',
  preact: 'h',
  nervjs: 'Nerv.createElement',
  hyperapp: 'h'
};

function createJSXRegexFor(dependency) {
  // result looks like /from\s+[`"']react[`"']|require\([`"']react[`"']\)/
  return new RegExp(`from\\s+[\`"']${dependency}[\`"']|require\\([\`"']${dependency}[\`"']\\)`);
}
/**
 * Solves a use case when JSX is used in .js files, but
 * package.json is empty or missing yet and therefore pragma cannot
 * be determined based on pkg.dependencies / pkg.devDependencies
 */


const cacheJsxRegexFor = {};

function maybeCreateFallbackPragma(asset) {
  for (const dep in JSX_PRAGMA) {
    let regex = cacheJsxRegexFor[dep];

    if (!regex) {
      regex = createJSXRegexFor(dep);
      cacheJsxRegexFor[dep] = regex;
    }

    if (asset.contents.match(regex)) {
      return JSX_PRAGMA[dep];
    }
  }
}
/**
 * Generates a babel config for JSX. Attempts to detect react or react-like libraries
 * and changes the pragma accordingly.
 */


function getJSXConfig(_x, _x2) {
  return _getJSXConfig.apply(this, arguments);
}

function _getJSXConfig() {
  _getJSXConfig = (0, _asyncToGenerator2.default)(function* (asset, isSourceModule) {
    // Don't enable JSX in node_modules
    if (!isSourceModule) {
      return null;
    }

    let pkg = yield asset.getPackage(); // Find a dependency that we can map to a JSX pragma

    let pragma = null;

    for (let dep in JSX_PRAGMA) {
      if (pkg && (pkg.dependencies && pkg.dependencies[dep] || pkg.devDependencies && pkg.devDependencies[dep])) {
        pragma = JSX_PRAGMA[dep];
        break;
      }
    }

    if (!pragma) {
      pragma = maybeCreateFallbackPragma(asset);
    }

    if (pragma || JSX_EXTENSIONS[path.extname(asset.name)]) {
      return {
        internal: true,
        babelVersion: 7,
        config: {
          plugins: [[require('@babel/plugin-transform-react-jsx'), {
            pragma,
            pragmaFrag: 'React.Fragment'
          }]]
        }
      };
    }
  });
  return _getJSXConfig.apply(this, arguments);
}

module.exports = getJSXConfig;