const babel = require('gulp-babel');
const gulp = require('gulp');
const print = require('gulp-print');


gulp.task('js', () => {
    return gulp.src('src/*.js')
        .pipe(print())
        .pipe( babel({ presets: ['es2015'] }))
        .pipe(gulp.dest('dist'));
});
const babel = require('gulp-babel');
const gulp = require('gulp');
const print = require('gulp-print');


gulp.task('build', () => {
    return gulp.src('src/*.js')
        .pipe(print())
        .pipe( babel({ presets: ['es2015'] }))
        .pipe(gulp.dest('dist'));
});

gulp.task('watch', () => {
    gulp.watch('src/*.js', ['build']);
});
Change task name from 'js' to 'build'
Change task name from 'js' to 'build'

Add 'watch' task to gulp to build compiled JS files on ES6 file change
