minifier.js

var through = require('through2');
var butternut = require('butternut');
var applySourceMap = require('vinyl-sourcemaps-apply');
var isObject = require('lodash/fp/isObject');
var zipObject = require('lodash/fp/zipObject');
var map = require('lodash/fp/map');
var prop = require('lodash/fp/prop');
var _ = require('lodash/fp/placeholder');
var defaultsDeep = require('lodash/fp/defaultsDeep');
var log = require('./lib/log');
var createError = require('./lib/create-error');
var GulpButternutError = require('./lib/gulp-butternut-error');

var reSourceMapComment = /\n\/\/# sourceMappingURL=.+?$/;

var defaultOptions = defaultsDeep({
    allowDangerousEval: false,
    sourceMap: true,
    check: false
});

function trycatch(fn, handle) {
    try {
        return fn();
    } catch (err) {
        return handle(err);
    }
}

function setup(opts) {

    if (opts && !isObject(opts)) {
        log.warn('gulp-butternut expects an object, non-object provided');
        opts = {};
    }

    var options = defaultOptions(opts);

    // if (options.preserveComments === 'all') {
    //     options.output.comments = true;
    // } else if (options.preserveComments === 'some') {
    //     // Preserve comments with directives or that start with a bang (!)
    //     options.output.comments = /^!|@preserve|@license|@cc_on/i;
    // } else if (options.preserveComments === 'license') {
    //     options.output.comments = saveLicense;
    // } else if (typeof options.preserveComments === 'function') {
    //     options.output.comments = options.preserveComments;
    // }

    return options;
}

module.exports = function(opts, butternut) {

    function minify(file, encoding, callback) {

        var options = setup(opts || {});
        var sources;

        if (file.isNull()) {
            return callback(null, file);
        }

        if (file.isStream()) {
            return callback(createError(file, 'Streaming not supported', null));
        }

        // if (file.sourceMap) {

        //     if (file.sourceMap.mappings) {
        //         options.inSourceMap = file.sourceMap;
        //     }

        //     options.outSourceMap = file.relative;

        //     sources = zipObject(
        //         file.sourceMap.sources,
        //         file.sourceMap.sourcesContent
        //     );

        // }

        var mangled = trycatch(function() {

            var source = String(file.contents);

            var m = butternut.squash(source, options);
            m.code = new Buffer(m.code.replace(reSourceMapComment, ''));

            return m;

        }, createError(file, 'unable to minify JavaScript'));

        if (mangled instanceof GulpButternutError) {
            return callback(mangled);
        }

        file.contents = mangled.code;

        // if (file.sourceMap) {

        //     var sourceMap = JSON.parse(mangled.map);
        //     sourceMap.sourcesContent = map(prop(_, sources), sourceMap.sources);

        //     applySourceMap(file, sourceMap);

        // }

        callback(null, file);
    }

    return through.obj(minify);
};