Breaks when logError tries to emit the end event

[DKvistgaard]

The logError function breaks the Gulp task as it tries to emit an end event.

After changing the logError function to an arrow function it has lost it's correct reference to the this operator, which causes it to break.
Instead of being a reference to the stream the this operator in this setup is a reference to gulpSass.

Versions

• gulp 3.9.1
• gulp-sass 4.0.0
• npm 5.8.0
• node 8.9.1

Gulp Task

gulp.task('styles', () => {
    return gulp.src('app/styles/style.scss')
        .pipe($.sass().on('error', $.sass.logError))
        .pipe(gulp.dest('dist/styles'));
});

Error Message

/node_modules/gulp-sass/index.js:156
  this.emit('end');
       ^

TypeError: this.emit is not a function
    at DestroyableTransform.gulpSass.logError (/node_modules/gulp-sass/index.js:156:8)
    at emitOne (events.js:121:20)
    at DestroyableTransform.emit (events.js:211:7)
    at onwriteError (/node_modules/readable-stream/lib/_stream_writable.js:354:10)
    at onwrite (/node_modules/readable-stream/lib/_stream_writable.js:371:11)
    at WritableState.onwrite (/node_modules/readable-stream/lib/_stream_writable.js:126:5)
    at afterTransform (/node_modules/readable-stream/lib/_stream_transform.js:81:3)
    at TransformState.afterTransform (/node_modules/readable-stream/lib/_stream_transform.js:58:12)
    at errorM (/node_modules/gulp-sass/index.js:118:12)
    at Object.callback (/node_modules/gulp-sass/index.js:127:16)

Idea for solution
Change the logError function declaration from:

gulpSass.logError = (error) => {
    ...
};

To:

gulpSass.logError = function logError(error) {
    ...
};

That way the logError gets its own this operator, which in this case is the desired stream and thereby the this.emit('end'); function will work again.

I'll happily create a PR for this fix if you wish.

[xzyfer]

What is $?

…

On Fri., 6 Apr. 2018, 7:31 pm Daniel Kvistgaard, ***@***.***> wrote: The logError function breaks the Gulp task as it tries to emit an end event. After changing the logError function to an arrow function it has lost it's correct reference to the this operator, which causes it to break. Instead of being a reference to the stream the this operator in this setup is a reference to gulpSass. *Versions* - gulp 3.9.1 - gulp-sass 4.0.0 - npm 5.8.0 - node 8.9.1 *Gulp Task* gulp.task('styles', () => { return gulp.src('app/styles/style.scss') .pipe($.sass().on('error', $.sass.logError)) .pipe(gulp.dest('dist/styles')); }); *Error Message* /node_modules/gulp-sass/index.js:156 this.emit('end'); ^ TypeError: this.emit is not a function at DestroyableTransform.gulpSass.logError (/node_modules/gulp-sass/index.js:156:8) at emitOne (events.js:121:20) at DestroyableTransform.emit (events.js:211:7) at onwriteError (/node_modules/readable-stream/lib/_stream_writable.js:354:10) at onwrite (/node_modules/readable-stream/lib/_stream_writable.js:371:11) at WritableState.onwrite (/node_modules/readable-stream/lib/_stream_writable.js:126:5) at afterTransform (/node_modules/readable-stream/lib/_stream_transform.js:81:3) at TransformState.afterTransform (/node_modules/readable-stream/lib/_stream_transform.js:58:12) at errorM (/node_modules/gulp-sass/index.js:118:12) at Object.callback (/node_modules/gulp-sass/index.js:127:16) — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#680>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAjZWIcmg5F9BUJNLuAHKIpJvy7lj6Wsks5tlzYMgaJpZM4TJxA4> .

[xzyfer]

I see. Yes there is a bug in gulp-sass 4. I'm not at a computer. I can make a patch in 24hrs

…

On Fri., 6 Apr. 2018, 8:17 pm Michael Mifsud, ***@***.***> wrote: What is $? On Fri., 6 Apr. 2018, 7:31 pm Daniel Kvistgaard, ***@***.***> wrote: > The logError function breaks the Gulp task as it tries to emit an end > event. > > After changing the logError function to an arrow function it has lost > it's correct reference to the this operator, which causes it to break. > Instead of being a reference to the stream the this operator in this > setup is a reference to gulpSass. > > *Versions* > > - gulp 3.9.1 > - gulp-sass 4.0.0 > - npm 5.8.0 > - node 8.9.1 > > *Gulp Task* > > gulp.task('styles', () => { > return gulp.src('app/styles/style.scss') > .pipe($.sass().on('error', $.sass.logError)) > .pipe(gulp.dest('dist/styles')); > }); > > *Error Message* > > /node_modules/gulp-sass/index.js:156 > this.emit('end'); > ^ > > TypeError: this.emit is not a function > at DestroyableTransform.gulpSass.logError (/node_modules/gulp-sass/index.js:156:8) > at emitOne (events.js:121:20) > at DestroyableTransform.emit (events.js:211:7) > at onwriteError (/node_modules/readable-stream/lib/_stream_writable.js:354:10) > at onwrite (/node_modules/readable-stream/lib/_stream_writable.js:371:11) > at WritableState.onwrite (/node_modules/readable-stream/lib/_stream_writable.js:126:5) > at afterTransform (/node_modules/readable-stream/lib/_stream_transform.js:81:3) > at TransformState.afterTransform (/node_modules/readable-stream/lib/_stream_transform.js:58:12) > at errorM (/node_modules/gulp-sass/index.js:118:12) > at Object.callback (/node_modules/gulp-sass/index.js:127:16) > > > — > You are receiving this because you are subscribed to this thread. > Reply to this email directly, view it on GitHub > <#680>, or mute the thread > <https://github.com/notifications/unsubscribe-auth/AAjZWIcmg5F9BUJNLuAHKIpJvy7lj6Wsks5tlzYMgaJpZM4TJxA4> > . >

[DKvistgaard]

@xzyfer Oh yeah $ is a reference to all gulp plugins loaded in with gulp-load-plugins. Just so we don't have to write a require statement for each gulp plugin in our gulpfile. :)

Ok great. Let me know if you need me to create a PR or need any further info.

[xzyfer]

Happy to accept a PR with a test 😀 If you look at the logError function at the bottom of the file. It's been mistakenly converted to an unbounded arrow function. That's why this is not defined.

…

On Fri., 6 Apr. 2018, 9:03 pm Daniel Kvistgaard, ***@***.***> wrote: Oh yeah $ is a reference to all gulp plugins loaded in with gulp-load-plugins. Just so we don't have to write a require statement for each gulp plugin in our gulpfile. :) Ok great. Let me know if you need me to create a PR or need any further info. — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#680 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAjZWDiBsNrQPoaToosRHlyW3RiOsHEJks5tl0uNgaJpZM4TJxA4> .