istanbul/lib/report/json.js

Yet another JS code coverage tool that computes statement, line, function and branch coverage with module loader hooks to transparently add coverage when running tests. Supports all JS coverage use cases including unit tests, server side functional tests

/*
 Copyright (c) 2012, Yahoo! Inc.  All rights reserved.
 Copyrights licensed under the New BSD License. See the accompanying LICENSE file for terms.
 */

var path = require('path'),
    Writer = require('../util/file-writer'),
    util = require('util'),
    Report = require('./index');
/**
 * a `Report` implementation that produces a coverage JSON object.
 *
 * Usage
 * -----
 *
 *      var report = require('istanbul').Report.create('json');
 *
 *
 * @class JsonReport
 * @extends Report
 * @module report
 * @constructor
 * @param {Object} opts optional
 * @param {String} [opts.dir] the directory in which to write the `coverage-final.json` file. Defaults to `process.cwd()`
 */
function JsonReport(opts) {
    this.opts = opts || {};
    this.opts.dir = this.opts.dir || process.cwd();
    this.opts.file = this.opts.file || this.getDefaultConfig().file;
    this.opts.writer = this.opts.writer || null;
}
JsonReport.TYPE = 'json';
util.inherits(JsonReport, Report);

Report.mix(JsonReport, {
    synopsis: function () {
        return 'prints the coverage object as JSON to a file';
    },
    getDefaultConfig: function () {
        return {
            file: 'coverage-final.json'
        };
    },
    writeReport: function (collector, sync) {
        var outputFile = path.resolve(this.opts.dir, this.opts.file),
            writer = this.opts.writer || new Writer(sync),
            that = this;

        writer.on('done', function () { that.emit('done'); });
        writer.writeFile(outputFile, function (contentWriter) {
            var first = true;
            contentWriter.println("{");
            collector.files().forEach(function (key) {
                if (first) {
                    first = false;
                } else {
                    contentWriter.println(",");
                }
                contentWriter.write(JSON.stringify(key));
                contentWriter.write(":");
                contentWriter.write(JSON.stringify(collector.fileCoverageFor(key)));
            });
            contentWriter.println("}");
        });
        writer.done();
    }
});

module.exports = JsonReport;