gulpfile.js

const gulp = require('gulp');
const eslint = require('gulp-eslint');
var babel = require("gulp-babel");
 
gulp.task('lint', () => {
    // ESLint ignores files with "node_modules" paths. 
    // So, it's best to have gulp ignore the directory as well. 
    // Also, Be sure to return the stream from the task; 
    // Otherwise, the task may end before the stream has finished. 
    return gulp.src(['src/**/*.js','!node_modules/**'])
        // eslint() attaches the lint output to the "eslint" property 
        // of the file object so it can be used by other modules. 
        .pipe(eslint({
          quiet: false //show warnnings.
        }))
        // eslint.format() outputs the lint results to the console. 
        // Alternatively use eslint.formatEach() (see Docs). 
        .pipe(eslint.format())
        // To have the process exit with an error code (1) on 
        // lint error, return the stream and pipe to failAfterError last. 
        .pipe(eslint.failAfterError());
});

// gulp.task("babel", function () {
//   return gulp.src("src/**/*.js")
//     .pipe(babel())
//     .pipe(gulp.dest("dist"));
// });
 
gulp.task('default', ['lint'], function () {
    // This will only run if the lint task is successful... 
  return gulp.src("src/**/*.js")
    .pipe(babel())
    .pipe(gulp.dest("dist"));
});

gulp.watch('src/**/*.js', ['default']);