javascript - How to use gulp-defer in gulp task? -

i having issue javascript loaded before page contents loaded decided use gulp-defer package in gulptask.

here code

// including plugins var gulp = require('gulp')     defer = require("gulp-defer");  // task gulp.task('concat', function () {     gulp.src('./javascript/*.js') // path files     .pipe(concat('concat.js'))  // concat , name "concat.js"     .pipe(gulp.dest('./dest')); }); gulp.task('html:release', function() {   return gulp.src('./index.html')    .pipe(defer())                  //defer method called     .pipe(gulp.dest('./dest')); }); 

i referred gulp-defer package.actually cant able understand how processed.please 1 explain how defer works in gulp task. in advance!!

not sure asking documentation self-explained:

moves render blocking javascript , css deferred loading section.

it helpful if "eliminate render-blocking javascript , css in above-the-fold content" warning pagespeed insights results

https://www.npmjs.com/package/gulp-defer