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Using Traceur with Node.js

George Yong edited this page Oct 14, 2016 · 11 revisions

Using Traceur 0.0.20 or later.

Traceur allows you to hook into Node.js' require function to allow you to require() ES6 modules just as if they were Node.js modules. (Note that the reverse process of using existing nodejs modules in ES6 is not yet supported in Traceur, see systemjs instead).

To do this you can either use traceur.require or you can make traceur.require the default by using traceur.require.makeDefault([filter, options]). Options are enumerated in Options.js. makeDefault optionally takes a filter function that takes the path to the file being required as input. If this function returns true Traceur will transform the file. Note: If you call makeDefault multiple times then traceur transpiles the file if at least one of the filter functions returned true.

Below is a more complete example:

// test.js
import {configFile} from './resources/b';  // use import for ES6 modules
var {readFileSync} = require('fs');  // use require for non-ES6 Node modules

console.log(readFileSync(configFile, 'utf-8'));
// resources/b.js
export var configFile = 'package.json';
// bootstrap.js
var traceur = require('traceur');
traceur.require.makeDefault(function(filename) {
  // don't transpile our dependencies, just our app
  return filename.indexOf('node_modules') === -1;
});
require('./test');
$ node bootstrap.js
{"contentsOf":"configFile"}

Note: The endsWith method gets injected into String.prototype with require('traceur').

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