require-hacker/scripts/watch.js

/**
 *  Copyright (c) 2015, Facebook, Inc.
 *  All rights reserved.
 *
 *  This source code is licensed under the BSD-style license found in the
 *  LICENSE file in the root directory of this source tree. An additional grant
 *  of patent rights can be found in the PATENTS file in the same directory.
 */

import sane from 'sane';
import { resolve as resolvePath } from 'path';
import { spawn } from 'child_process';

process.env.PATH += ':./node_modules/.bin';

const is_windows = process.platform === 'win32'

// still creates the NUL file in the current working directory
const dev_null = is_windows ? 'NUL' : '/dev/null'

var cmd = resolvePath(__dirname);
var srcDir = resolvePath(cmd, './source');

function exec(command, options) {
  return new Promise(function (resolve, reject) {
    var child = spawn(command, options, {
      cmd: cmd,
      env: process.env,
      stdio: 'inherit'
    });
    child.on('exit', function (code) {
      if (code === 0) {
        resolve(true);
      } else {
        reject(new Error('Error code: ' + code));
      }
    });
  });
}

var watcher = sane(srcDir, { glob: ['**/*.*'] })
  .on('ready', startWatch)
  .on('add', changeFile)
  .on('delete', deleteFile)
  .on('change', changeFile);

process.on('SIGINT', function () {
  watcher.close();
  console.log(CLEARLINE + yellow(invert('stopped watching')));
  process.exit();
});

var isChecking;
var needsCheck;
var toCheck = {};
var timeout;

function startWatch() {
  process.stdout.write(CLEARSCREEN + green(invert('watching...')));
}

function changeFile(filepath, root, stat) {
  if (!stat.isDirectory()) {
    toCheck[filepath] = true;
    debouncedCheck();
  }
}

function deleteFile(filepath) {
  delete toCheck[filepath];
  debouncedCheck();
}

function debouncedCheck() {
  needsCheck = true;
  clearTimeout(timeout);
  timeout = setTimeout(guardedCheck, 250);
}

function guardedCheck() {
  if (isChecking || !needsCheck) {
    return;
  }
  isChecking = true;
  var filepaths = Object.keys(toCheck);
  toCheck = {};
  needsCheck = false;
  checkFiles(filepaths).then(() => {
    isChecking = false;
    process.nextTick(guardedCheck);
  });
}

function checkFiles(filepaths) {
  console.log('\u001b[2J');

  // return parseFiles(filepaths)
  //   .then(() => runTests(filepaths))
  return runTests(filepaths)
    .catch(() => false)
    .then(success => {
      process.stdout.write(
        '\n' + (success ? '' : '\x07') + green(invert('watching...'))
      );
    });
}

// Checking steps

function executable(command) {
  if (is_windows) {
    return command + '.cmd'
  }
  return command
}

function parseFiles(filepaths) {
  console.log('Checking Syntax');

  return Promise.all(filepaths.map(filepath => {
    if (isJS(filepath) && !isTest(filepath)) {
      return exec(executable('babel'), [
        '--optional', 'runtime',
        '--out-file', dev_null,
        srcPath(filepath)
      ]);
    }
  }));
}

function runTests(filepaths) {
  console.log('\nRunning Tests');

  return exec(executable('mocha'), [
    '--reporter', 'spec',
    '--bail',
    '--require', 'scripts/mocha-bootload'
  ].concat(
    allTests(filepaths) ? filepaths.map(srcPath) : ['test/**/*.js'] // 'src/**/__tests__/**/*.js'
  )).catch(() => false);
}

// Filepath

function srcPath(filepath) {
  return resolvePath(srcDir, filepath);
}

// Predicates

function isJS(filepath) {
  return filepath.indexOf('.js') === filepath.length - 3;
}

function allTests(filepaths) {
  return filepaths.length > 0 && filepaths.every(isTest);
}

function isTest(filepath) {
  return isJS(filepath) && ~filepath.indexOf('__tests__/');
}

// Print helpers

var CLEARSCREEN = '\u001b[2J';
var CLEARLINE = '\r\x1B[K';
var CHECK = green('\u2713');
var X = red('\u2718');

function invert(str) {
  return `\u001b[7m ${str} \u001b[27m`;
}

function red(str) {
  return `\x1B[K\u001b[1m\u001b[31m${str}\u001b[39m\u001b[22m`;
}

function green(str) {
  return `\x1B[K\u001b[1m\u001b[32m${str}\u001b[39m\u001b[22m`;
}

function yellow(str) {
  return `\x1B[K\u001b[1m\u001b[33m${str}\u001b[39m\u001b[22m`;
}