Gulp watch callback task not firing

Question

I'm trying to set up a gulp-watch which triggers a gulp task when some files change. For this purpose I'm using the following code:

gulp.task('watchChanges', function(cb){
    console.log("Looking for file changes in " + watchPath+".");  

    return watch(watchPath, ['FilesChanged']);
});

gulp.task('FilesChanged', function (cb){
    FilesChanged();
    cb();
})

function FilesChanged()
{
    console.log("Files changed:")
}

Whenever the files change I would like it if the 'FilesChanged' task would fire and I'd see the "Files changed:" text in console. This doesn't happen.

When I change my watchChanges task to this:

gulp.task('watchChanges', function(cb){
    console.log("Looking for file changes in " + watchPath+".");  

    return watch(watchPath, FilesChanged);
});

Can anyone explain why the first piece of code does not execute correctly?

Do you have your own watch function that you are calling or do intend to use gulp.watch? If you have a watch function what does it look like? Are you using gulp-watch there? We need more information. Gulp-watch can be passed a function as you have it in the working example but not a list of task names. — Mark, Jul 27 '17 at 00:51
@Mark I am using gulp-watch. I forgot to include a part of my code in the example: `var gulp = require('gulp'); var watch = require('gulp-watch');` — Jasper Callens, Jul 27 '17 at 07:36

Mark · Answer 1 · 2017-07-27T18:57:31.820

Since you are using gulp-watch if you look at its function definition:

watch(glob, [options, callback])

you can see that it will take a callback function which is why your

return watch(watchPath, FilesChanged);

works and

return watch(watchPath, ['FilesChanged']);

does not. gulp-watch will not take an array of tasks like gulp.watch will:

gulp.watch(glob[, opts], tasks)

gulp-watch and gulp.watch are two entirely different things. What you probably want is

gulp.task('watchChanges', function(cb){
    console.log("Looking for file changes in " + watchPath+".");  

    gulp.watch(watchPath, ['FilesChanged']);
});

If you then to see which files are being processed, try one of the suggestions from get the current file name.

Thanks for your response. I had indeed looked over the function defintions for watch and gulp-watch. I have correct my code to your last example but I still do not get the required result. So this works: `watch(watchPath, FilesChanged) .pipe(debug());` But this does not: `gulp.watch(watchPath, ['FilesChanged']) .pipe(debug());` — Jasper Callens, Jul 28 '17 at 08:28

Gulp watch callback task not firing

1 Answers1