gulpfile.js

const gulp = require('gulp');
const eslint = require('gulp-eslint');

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.
     gulp.src(['**/*.js', '!node_modules/**', '!dist/**'])
    // eslint() attaches the lint output to the "eslint" property
    // of the file object so it can be used by other modules.
        .pipe(eslint())
        // 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('default', ['lint']);

gulp.task('watch', () => {
  gulp.watch(['**/*.js', '!node_modules/**', '!dist/**'], ['lint']);
});