gulpfile.js

var gulp = require('gulp');
var through = require('through2');
var gutil = require('gulp-util');
var merge = require('merge-stream');
var del = require('del');
var fs = require('fs');
var path = require('path');
var _ = require('lodash');
var win32 = process.platform === "win32";
var spawn = require('child_process').spawn;
var babel = require("gulp-babel");
var tslint = require("gulp-tslint");
var sourcemaps = require("gulp-sourcemaps");
var gulpPath = path.join(__dirname, 'node_modules/.bin/gulp' + (win32 && '.cmd' || ''));
var typescript = require('typescript');
var ts = require('gulp-typescript');
var tsProject = ts.createProject('tsconfig.json', { sourceMap: false, typescript: typescript });

var metadata = {
    lib: ['lib/**/*.ts', '!lib/**/*.d.ts'],
    spec: ['spec/**/*.ts', '!spec/**/*.d.ts'],
};

gulp.task('typescript', ['clean'], function () {
    return tsProject.src()
        // .pipe(tslint({
        //     formatter: "verbose"
        // }))
        // .pipe(tslint.report())
        .pipe(sourcemaps.init())
        .pipe(tsProject())
        .pipe(babel())
        .pipe(sourcemaps.write())
        .pipe(gulp.dest('.'));
});

gulp.task('dist', ['typescript'], function () {
    return gulp.src(['lib/**/*.js'])
        .pipe(gulp.dest('dist'));
});

gulp.task('clean', ['clean:lib', 'clean:dist', 'clean:spec']);

gulp.task('clean:dist', function (done) {
    del(['dist/**/*.js']).then(function (paths) {
        _.each(paths, function (path) {
            gutil.log(gutil.colors.red('Deleted ') + gutil.colors.magenta(path.replace(__dirname, '').substring(1)));
        });
        done();
    });
});

gulp.task('clean:lib', function (done) {
    del(metadata.lib.map(function (z) {
        return gutil.replaceExtension(z, '.js');
    })).then(function (paths) {
        _.each(paths, function (path) {
            gutil.log(gutil.colors.red('Deleted ') + gutil.colors.magenta(path.replace(__dirname, '').substring(1)));
        });
        done();
    });
});

gulp.task('clean:spec', function (done) {
    del(metadata.spec.map(function (z) {
        return gutil.replaceExtension(z, '.js');
    })).then(function (paths) {
        _.each(paths, function (path) {
            gutil.log(gutil.colors.red('Deleted ') + gutil.colors.magenta(path.replace(__dirname, '').substring(1)));
        });
        done();
    });
});

gulp.task('watch', function () {
    // Watch is not installed by default if you want to use it
    //  you need to install manually but don't save it as it causes CI issues.
    var watch = require('gulp-watch');
    // Auto restart watch when gulpfile is changed.
    var p = spawn(gulpPath, ['file-watch'], {
        stdio: 'inherit'
    });
    return watch('gulpfile.js', function () {
        p.kill();
        p = spawn(gulpPath, ['file-watch'], {
            stdio: 'inherit'
        });
    });
});

gulp.task('npm-postinstall', []);
gulp.task('npm-prepublish', ['dist']);

// The default task (called when you run `gulp` from CLI)
gulp.task('default', ['typescript']);