gulpfile.js

const gulp = require("gulp");
const babel = require("gulp-babel");
const plumber = require("gulp-plumber");

const src = ["./src/**/*.jsx", "./src/**/*.js", "!./src/**/__tests__/**"];

const buildEs = () => gulp.src(src).pipe(gulp.dest("./es"));

const buildLib = () =>
  gulp
    .src(src)
    .pipe(plumber())
    .pipe(
      babel({
        babelrc: true
      })
    )
    .pipe(gulp.dest("./lib"));

const flowEs = () => gulp.src("./src/**/*.js.flow").pipe(gulp.dest("./es"));
const flowLib = () => gulp.src("./src/**/*.js.flow").pipe(gulp.dest("./lib"));
const tsEs = () => gulp.src("./src/**/*.d.ts").pipe(gulp.dest("./es"));
const tsLib = () => gulp.src("./src/**/*.d.ts").pipe(gulp.dest("./lib"));

const build = gulp.series(
  gulp.parallel(buildEs, buildLib),
  gulp.parallel(flowEs, flowLib),
  gulp.parallel(tsEs, tsLib)
);

module.exports = {
  build
};