Document updated gulp.watch syntax for gulp 4.0

[kincaidoneil]

I recently updated to the 4.0 branch, however, I'm experiencing an issue in which using a function as a callback to gulp.watch results in nothing being based through to the event variable, as I particularly use event.path.

Here's my code:

gulp.watch('app/index.html', function(event) {
    console.log(event);
    console.log(event.path);
});

Here's what the console returns after the file is updated:

[Function: done]
undefined

Even if I pass through gulp.series('name_of_task_here'), it passes through the same thing to the first parameter.

Is there anything I'm doing wrong/was this method deprecated in gulp 4.0? If so, is there a better alternative?

Thanks!

[heikki]

https://github.com/gulpjs/gulp/blob/master/docs/API.md#tasks

i.e. you can listen for change events, docs don't seem to be up to date

[phated]

The watch syntax is changing in 4.0. Since everything is based on function composition, the watch tasks receive an async done callback (and handles streams/promises/etc being returned).

If you need to access the event object, use:

var watcher = gulp.watch('app/index.html');
watcher.on('change', function(event){

});

[phated]

Changing title to "Document updated watch syntax"

[yocontra]

Should be in the changelog on the 4.0 branch

[phated]

Done! - Thanks @dinoboff

[lkraav]

watcher.on('change', function(event){

Is watcher.on('add change', function(event){ also supposed to work? It's not firing for me, while 'change' alone is.

[phated]

I doubt it, the emitter is just a node EventEmitter as far as I am aware. Please review chokidar docs for event support.