gulpfile.js

const gulp = require("gulp");
const del = require("del");
const vinylPaths = require("vinyl-paths");
const runSequence = require("run-sequence");
const ts = require("gulp-typescript");
const to5 = require("gulp-babel");
const replace = require("gulp-replace");

const tsProject = ts.createProject("tsconfig.json", {
  typescript: require("typescript")
});

const outputPath = "dist/";
const dtsFile = outputPath + "uploader.d.ts";

gulp.task("clean", function() {
  return gulp.src([outputPath])
             .pipe(vinylPaths(del));
});

gulp.task("build-dts", function() {
  return require("dts-generator").default({
    name: "uploader",
    baseDir: "./src",
    files: ["index.ts"],
    out: dtsFile
  });
});

gulp.task("dts-fix", function() {
  return gulp.src(dtsFile)
             .pipe(replace("declare module 'uploader/index'", "declare module 'uploader'"))
             .pipe(gulp.dest(outputPath));
});

gulp.task('build-common', function() {
    return gulp.src(["src/**/*.ts", "typings/**/*.d.ts"])
               .pipe(ts(tsProject))
               .pipe(to5({
                 modules: "common"
               }))
               .pipe(gulp.dest(outputPath));
});

gulp.task('build', function(callback) {
    return runSequence(
             'clean',
             'build-common',
             'build-dts',
             'dts-fix',
             callback);
});