v2.0.3 Undefined is not a function

[chyld]

Ran into this error when using v2.0.3.
I'm on Mac OSX 10.10 running Node 0.12 64-bit.

Users/chyld/Code/calculator/node_modules/gulp-less/index.js:68
    }).done(undefined, cb);
       ^
TypeError: undefined is not a function
    at DestroyableTransform._transform (/Users/chyld/Code/calculator/node_modules/gulp-less/index.js:68:8)
    at DestroyableTransform.Transform._read (/Users/chyld/Code/calculator/node_modules/gulp-less/node_modules/through2/node_modules/readable-stream/lib/_stream_transform.js:184:10)
    at DestroyableTransform.Transform._write (/Users/chyld/Code/calculator/node_modules/gulp-less/node_modules/through2/node_modules/readable-stream/lib/_stream_transform.js:172:12)
    at doWrite (/Users/chyld/Code/calculator/node_modules/gulp-less/node_modules/through2/node_modules/readable-stream/lib/_stream_writable.js:237:10)
    at writeOrBuffer (/Users/chyld/Code/calculator/node_modules/gulp-less/node_modules/through2/node_modules/readable-stream/lib/_stream_writable.js:227:5)
    at DestroyableTransform.Writable.write (/Users/chyld/Code/calculator/node_modules/gulp-less/node_modules/through2/node_modules/readable-stream/lib/_stream_writable.js:194:11)
    at write (/Users/chyld/Code/calculator/node_modules/gulp/node_modules/vinyl-fs/node_modules/through2/node_modules/readable-stream/lib/_stream_readable.js:623:24)
    at flow (/Users/chyld/Code/calculator/node_modules/gulp/node_modules/vinyl-fs/node_modules/through2/node_modules/readable-stream/lib/_stream_readable.js:632:7)
    at DestroyableTransform.pipeOnReadable (/Users/chyld/Code/calculator/node_modules/gulp/node_modules/vinyl-fs/node_modules/through2/node_modules/readable-stream/lib/_stream_readable.js:664:5)
    at DestroyableTransform.emit (events.js:104:17)

[stephenlacy]

Please add your gulp task

[baldore]

I'm having the same error. Gulp-less works when I use node 0.10.36, but doesn't run when I set node 0.12 or IO.js 1.1.0. This is my task.

gulp.task('less', function () {
  gulp.src('main.less')
    .pipe(less())
    .on('error', console.error.bind(console))
    .pipe(gulp.dest('css/'));
});

[chyld]

My gulp task

gulp.task('less', function() {
  gulp.src(paths.lesssrc)
    .pipe(less())
    .on('error', function (err) {
      console.log(err);
    })
    .pipe(gulp.dest(paths.lessdst));
});

[yocontra]

@ohJeez looks like your PR broke for node 0.12 and io.js - any ideas?

[mattstyles]

Looks like less.render expects a success and error handler rather than exposing then, done and catch.

The fix is to move the catch handler into param 2 of then and discard the done handler as I think its redundant as the then handler dispatches the "master" callback. This certainly fixes a failing and passing compile using iojs (Ive not idea why this works in 0.10.x). I cant be sure exactly that this is anything more than a sticky-taping over something as I'm not sure the original intention of @ohJeez's PR.

Regarding 0.10.x, no idea why it still works, looks like node is simply ignoring the .catch and .done, logging the return of .then just gives another chainable .then with no catch or done methods to call. I'm going to assume this is a bug with 0.10.x and that 0.12 and 1.x behave as you would expect, but havent done a great deal of digging.

I'm happy to issue a PR, but, like I say, I'm not sure of the original intention of the PR.

[OJezu]

Native promise does not have .done, while then/promise has. Less includes then/promise only if no native promises are available.
https://github.com/less/less.js/blob/fb5280f16f124e5062634a22be2f3c99e650d0a4/lib/less/render.js#L12

Quick fix will be replacing .done with .then. Good fix will be always including then/promise in less/less.js . I will open an issue there.

[mattstyles]

Yeah, I just did some digging and found the same.

You mean replace .done with another .then?

[OJezu]

@mattstyles It will work. .done is better, but .then is all we have.

[mattstyles]

@ohJeez yep, I gotcha, I was just referring to the typo in your earlier comment.

[mattstyles]

@ohJeez although, you know that final .then wont ever be called and is redundant in es6?

[OJezu]

@mattstyles why? It has arguments.

[mattstyles]

@ohJeez yeah, but the .catch will grab any errors and throw, I'm just going to check but I thought that would end the chain. Thinking about it I guess the error propagates to the final .then.

[OJezu]

@mattstyles, not if there is another error thrown inside the .catch() handler. That was one of the reasons of the #118 - there was another error thrown in handler and never caught. That .done() was supposed to be the last resort try to pass something to callback.

[mattstyles]

@ohJeez oh yeah, I see now, propagates straight down, makes sense I guess. Although that throws up a slightly different issue, it consumes the error so gulp thinks the less compile has been successful. I cant catch the error in the stream, unless I'm missing something?

[mattstyles]

@ohJeez Ignore my previous comment, plumber will catch the error rather than using .on( 'error' ).

[yocontra]

Can you try 3.0.0? @Jenius just sent a major PR which switches us from using less directly to using a less wrapper which handles all of this weird shit. the stuff less exports is a pain to deal with

[jumoel]

I experienced the same error, and it disappeared on 3.0.0.

[jescalan]

🎉

[JalalAlbasri]

ty, 3.0.0 working for me too 👍