pulsar/spec/babel-spec.js

// Users may have this environment variable set. Currently, it causes babel to
// log to stderr, which causes errors on Windows.
// See https://github.com/atom/electron/issues/2033
process.env.DEBUG = '*';

const path = require('path');
const temp = require('temp').track();
const CompileCache = require('../src/compile-cache');

describe('Babel transpiler support', function() {
  let originalCacheDir = null;

  beforeEach(function() {
    originalCacheDir = CompileCache.getCacheDirectory();
    CompileCache.setCacheDirectory(temp.mkdirSync('compile-cache'));
    // TODO: rework to avoid using IIFE https://developer.mozilla.org/en-US/docs/Glossary/IIFE
    return (() => {
      const result = [];
      for (let cacheKey of Object.keys(require.cache)) {
        if (cacheKey.startsWith(path.join(__dirname, 'fixtures', 'babel'))) {
          result.push(delete require.cache[cacheKey]);
        } else {
          result.push(undefined);
        }
      }
      return result;
    })();
  });

  afterEach(function() {
    CompileCache.setCacheDirectory(originalCacheDir);
    try {
      return temp.cleanupSync();
    } catch (error) {}
  });

  describe('when a .js file starts with /** @babel */;', () =>
    it('transpiles it using babel', function() {
      const transpiled = require('./fixtures/babel/babel-comment.js');
      expect(transpiled(3)).toBe(4);
    }));

  describe("when a .js file starts with 'use babel';", () =>
    it('transpiles it using babel', function() {
      const transpiled = require('./fixtures/babel/babel-single-quotes.js');
      expect(transpiled(3)).toBe(4);
    }));

  describe('when a .js file starts with "use babel";', () =>
    it('transpiles it using babel', function() {
      const transpiled = require('./fixtures/babel/babel-double-quotes.js');
      expect(transpiled(3)).toBe(4);
    }));

  describe('when a .js file starts with /* @flow */', () =>
    it('transpiles it using babel', function() {
      const transpiled = require('./fixtures/babel/flow-comment.js');
      expect(transpiled(3)).toBe(4);
    }));

  describe('when a .js file starts with // @flow', () =>
    it('transpiles it using babel', function() {
      const transpiled = require('./fixtures/babel/flow-slash-comment.js');
      expect(transpiled(3)).toBe(4);
    }));

  describe("when a .js file does not start with 'use babel';", function() {
    it('does not transpile it using babel', function() {
      spyOn(console, 'error');
      expect(() => require('./fixtures/babel/invalid.js')).toThrow();
    });

    it('does not try to log to stdout or stderr while parsing the file', function() {
      spyOn(process.stderr, 'write');
      spyOn(process.stdout, 'write');

      require('./fixtures/babel/babel-double-quotes.js');

      expect(process.stdout.write).not.toHaveBeenCalled();
      expect(process.stderr.write).not.toHaveBeenCalled();
    });
  });
});