grunt-json-merger/tasks/grunt-json-merger.js

Grunt Task for Merging Multiple JSON Files

/*
 **  grunt-json-merger -- Grunt Task for Merging Multiple JSON Files
 **  Copyright (c) 2013-2014 Ralf S. Engelschall <rse@engelschall.com>
 **  Copyright (c) 2016 Peter Fredricks <pete@goosetail.com>
 **
 **  Permission is hereby granted, free of charge, to any person obtaining
 **  a copy of this software and associated documentation files (the
 **  "Software"), to deal in the Software without restriction, including
 **  without limitation the rights to use, copy, modify, merge, publish,
 **  distribute, sublicense, and/or sell copies of the Software, and to
 **  permit persons to whom the Software is furnished to do so, subject to
 **  the following conditions:
 **
 **  The above copyright notice and this permission notice shall be included
 **  in all copies or substantial portions of the Software.
 **
 **  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 **  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 **  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 **  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 **  CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 **  TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 **  SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

/* global module: false */
module.exports = function (grunt) {
	/* global require: false */
	var chalk = require("chalk");
	var _ = require("lodash");

	grunt.registerMultiTask("json-merger", "Merge Multiple JSON Files", function () {
		/*  prepare options  */
		var options = this.options({
			replacer: null,
			space: "\t"
		});
		grunt.verbose.writeflags(options, "Options");

		/*  iterate over all src-dest file pairs  */
		this.files.forEach(function (f) {
			try {
				/*  start with an empty object  */
				var json = {};
				f.src.forEach(function (src) {
					/*  merge JSON file into object  */
					if (!grunt.file.exists(src))
						throw "JSON source file \"" + chalk.red(src) + "\" not found.";
					else {
						var fragment;
						grunt.log.debug("reading JSON source file \"" + chalk.green(src) + "\"");
						try {
							fragment = grunt.file.readJSON(src);
						}
						catch (e) {
							grunt.fail.warn(e);
						}
						json = _.merge(json, fragment, function (a, b) {
							return _.isArray(a) ? a.concat(b) : undefined;
						});
					}
				});

				/*  write object as new JSON  */
				grunt.log.debug("writing JSON destination file \"" + chalk.green(f.dest) + "\"");
				grunt.file.write(f.dest, JSON.stringify(json, options.replacer, options.space));
				grunt.log.writeln("File \"" + chalk.green(f.dest) + "\" created.");
			}
			catch (e) {
				grunt.fail.warn(e);
			}
		});
	});
};