gulpfile.js

const gulp = require('gulp');
const ts = require('gulp-typescript');
const srcmap = require('gulp-sourcemaps');
const path = require('path');
const tslint = require('gulp-tslint');
const rmrf = require("rimraf");
// const rollup = require("gulp-rollup");
// const commonjs = require("rollup-plugin-commonjs");
// const json = require("rollup-plugin-json");
// const rename = require("gulp-rename");
// const babel = require("rollup-plugin-babel");


const projectOpts = ts.createProject({
  target: "es6",
  module: "commonjs",
  noImplicitAny: false,
  declaration: true,
  noResolve: true,
  allowSyntheticDefaultImports: true
});

// This will not throw on errors, just report them. For developing.
gulp.task('source', () => {
  let result = gulp.src(['src/**/*.ts', 'typings/**/*.ts'])
    .pipe(srcmap.init())
    .pipe(projectOpts());

  result.js
    .pipe(srcmap.write({sourceRoot: path.resolve(__dirname, "src")}))
    .pipe(gulp.dest("dist/"));

  result.dts.pipe(gulp.dest("defs/"));

  // return merge([
  //   result.js
  //     .pipe(srcmap.write({sourceRoot: path.resolve(__dirname, "src")}))
  //     .pipe(gulp.dest('dist/')),
  //   result.dts.pipe(gulp.dest('dist/'))
  // ]);
});

// Clean out the dist/ directory
gulp.task("clean", () => {
  rmrf.sync("dist/");
  rmrf.sync("defs/");
});

// This will throw on errors. For publishing.
gulp.task('lint', () => {
  gulp.src('src/**/*.ts')
    .pipe(tslint({
      formatter: "verbose"
    }))
    .pipe(tslint.report());
});

// Generate definition files for publishing, will throw on err
gulp.task("gen-dt", () => {
  const res = gulp.src(["src/**/*.ts", "typings/**/*.ts"])
    .pipe(projectOpts())
    .on("error", err => {throw err});

  res.dts.pipe(gulp.dest("defs/"))
});

// Run tasks before publishing to npm. Will throw on errors.
gulp.task('pub', ["clean", 'lint', 'source']);

// This will report errors and swallow them so that dev doesn't restart
gulp.task('dev', ["clean", 'source'], () => {
  gulp.watch('src/**/*.ts', ["source", "lint"]).on("error", () => {});
});