How to connect gulp-autoprefixer in gulpfile.js?

There gulpfile.js when you type the command gulp watch run browser-sync and sass compiler, you also need to connect gulp-autoprefixe not understand how to do, help would be very grateful (myself gulp-autoprefixer)
var gulp = require('gulp'), 
 sass = require('gulp-sass'), 
 browserSync = require('browser-sync'); 


gulp.task('sass', function(){ 
 return gulp.src(['app/sass/**/*.sass', 'app/sass/**/*.scss']) 
 .pipe(sass({outputStyle: 'expanded'}).on('error', sass.logError)) 
 .pipe(gulp.dest('app/css')) 
 .pipe(browserSync.reload({stream: true})) 
});

gulp.task('browser-sync', function() { 
 browserSync({ 
proxy:"Site",
 notify: false 
});
});

gulp.task('watch', ['browser-sync', 'sass'], function() {
 gulp.watch(['app/sass/**/*.sass', 'app/sass/**/*.scss'], ['sass']); 
 gulp.watch("**/*.php", browserSync.reload);
 gulp.watch("app/include/*.html", browserSync.reload);
 gulp.watch("app/js/*.js", browserSync.reload);
});
June 7th 19 at 14:57
2 answers
June 7th 19 at 14:59
Solution
npm i gulp-autoprefixer -S

var gulp = require('gulp'), 
 sass = require('gulp-sass'), 
autoprefixer = require('gulp-autoprefixer'),
 browserSync = require('browser-sync'); 


gulp.task('sass', function(){ 
 return gulp.src(['app/sass/**/*.sass', 'app/sass/**/*.scss']) 
 .pipe(sass({outputStyle: 'expanded'}).on('error', sass.logError))
 .pipe(autoprefixer(['last 15 versions', '> 1%', 'ie 8', 'ie 7'], { cascade: true }))
 .pipe(gulp.dest('app/css')) 
 .pipe(browserSync.reload({stream: true})) 
});
what does this mean?
'last 15 versions', '> 1%', 'ie 8', 'ie 7' - Jannie.Jacobi commented on June 7th 19 at 15:02
what browser versions are needed .you better read the manuals for this plugin=) - jarrell commented on June 7th 19 at 15:05
June 7th 19 at 15:01
Connected to output gulp-sass'a:

var autoprefixer = require('gulp-autoprefixer');
var config = ... // your config for autoprefix
...
gulp.task('sass', function(){ 
 return gulp.src(['app/sass/**/*.sass', 'app/sass/**/*.scss']) 
 .pipe(sass({outputStyle: 'expanded'}).on('error', sass.logError)) 
.pipe(autoprefixer(config))
 .pipe(gulp.dest('app/css')) 
 .pipe(browserSync.reload({stream: true})) 
});
...

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