index.js

'use strict';

var extend = require('node.extend');
var through = require('through');
var path = require('path');
var gutil = require('gulp-util');
var PluginError = gutil.PluginError;
var File = gutil.File;

var PLUGIN_NAME = 'gulp-extend';

module.exports = function(fileName, deep, jsonSpace) {
  if (!fileName) {
    throw new PluginError(PLUGIN_NAME, PLUGIN_NAME + ': Missing fileName parameter');
  }

  var buffer = [];
  var firstFile = null;

  deep = (deep !== undefined) ? deep : true;
  buffer.push(deep); // first argument

  function bufferContents(file) {
    if (file.isNull()) {
      return this.queue(file);
    }

    if (file.isStream()) {
      return this.emit('error', new PluginError(PLUGIN_NAME, PLUGIN_NAME + ': Streaming not supported'));
    }

    if (!firstFile) {
      firstFile = file;
    }

    var jsonContent;

    try {
      jsonContent = JSON.parse(file.contents.toString('utf8'));
    } catch (e) {
      jsonContent = {};
      console.log('[' + gutil.colors.red('gulp-extend') + '] File "' + file.path + '" has errors and was skipped!');
    }

    buffer.push(jsonContent);
  }

  function endStream() {
    if (buffer.length === 1) {
      return this.emit('end');
    }

    var joinedContents = extend.apply(this, buffer);
    var joinedPath = path.join(firstFile.base, fileName);
    var joinedFile = new File({
      cwd: firstFile.cwd,
      base: firstFile.base,
      path: joinedPath,
      contents: new Buffer(JSON.stringify(joinedContents, null, jsonSpace))
    });

    this.emit('data', joinedFile);
    this.emit('end');
  }

  return through(bufferContents, endStream);
};