I'm working on a JS library and I want to transpile all javascript code written in ES6 to ES5 standard to get more support in current browsers.

The thing is I want to use Babel with the Gulp tasks, so I've installed all this NPM packages [package.json]:

"devDependencies": {
  "@babel/core": "^7.1.2",
  "@babel/preset-env": "^7.1.0",
  "babel-cli": "^6.26.0",
  "gulp": "^3.9.1",
  "gulp-babel": "^8.0.0",
  "gulp-concat": "^2.6.1",
  "gulp-sourcemaps": "^2.6.4",
  "gulp-terser": "^1.1.5"
}

Next my .babelrc file has the following content:

{
  "presets": ["env"]
}

And the gulpfile.js is written as following:

const gulp = require('gulp');
const sourcemaps = require('gulp-sourcemaps');
const babel = require('gulp-babel');
const concat = require('gulp-concat');
const terser = require('gulp-terser');

gulp.task('minify', function () {
    return gulp.src('src/app/classes/*.js')
        .pipe(sourcemaps.init()) 
        .pipe(babel())     // I do not pass preset, because .babelrc do exist
        .pipe(concat('output.js'))   
        .pipe(sourcemaps.write('.'))   
        .pipe(gulp.dest('build/js'))
});

gulp.task('default', ['minify']);

The issue is when I execute the gulp command on the project root directory, it not produce output file. The console shows a successful execution but nothing appears inside build/js directory, or neither inside another directory of the project.

#user1:/project-route$> gulp
    [17:36:54] Using gulpfile /project-route/gulpfile.js
    [17:36:54] Starting 'minify'...

I also tried without sourcemaps functions and the result is the same, nothing!!!.

For an extrange reason, when I execute in terminal babel -V the result is:

#user1:/project-route$> gulp
    6.26.0 (babel-core 6.26.3)

This is not the same version I installed (that I remember):

"@babel/core": "^7.1.2", 
"@babel/preset-env": "^7.1.0",

So, I uninstalled all this dependencies:

"@babel/core": "^7.1.2",
"@babel/preset-env": "^7.1.0",
"gulp-babel": "^8.0.0",

And I installed this ones in replacement:

"babel-core": "^6.26.3",
"babel-preset-env": "^1.7.0",
"gulp-babel": "^7.0.1",

And all functions works now!!!

---

Of course, the explanation is accordingly to this note on the README.md of the gulp-babel plugin, realizing about this matter cost me a lot of headaches:

Install guide (gulp-babel on GitHub)

Install

Install gulp-babel if you want to get the pre-release of the next version of gulp-babel.

# Babel 7
$ npm install --save-dev gulp-babel @babel/core @babel/preset-env

# Babel 6
$ npm install --save-dev gulp-babel@7 babel-core babel-preset-env