Terminate gulp-watch task - gulp-watch

Question

I want my gulp watch task to run only once, then stop watching. Now, if I run 'gulp' from the command line, the watch tasks keeps the gulp task running. I have to hit Ctrl-C to stop it.

Answer 1

when you run gulp watch, it will keep watching for file changes until you cancel it with CTRL-C. I you do not want this, then you can make a separate gulp task to do your building.
You would have 2 tasks then: gulp watch and gulp build. As the build wouldn't run the watch task, it will stop when finished.
Please take a look at a GitHub project of mine where I do things like this: skeletonSPA on GitHub.
If you take a look at the gulpfile.js, you see that the default task will execute the build task.
The build task on its turn will execute info, clean, styles, scripts, images, copy, todo; leaving you with a full build and working frontend.
After running these tasks, it will stop and gives you focus to the command line.

Answer 2

Here's a very basic example GulpFile.js:
var gulp = require('gulp'),
watch = require('gulp-watch'),
runSequence = require('gulp-sequence'),
webpack = require('webpack-stream');
gulp.task('webpack', function() {
return gulp.src('client/index.js')
.pipe(webpack({
output: {
filename: 'dist/bundle.js'
},
devtool: 'source-map'
}))
.pipe(gulp.dest('.'));
});
// other tasks
gulp.task('build', ['webpack', 'other tasks... ']);
gulp.task('watch', function(callback) {
gulp.watch('./client/**/*.js', {}, ['webpack']);
// more watches if required
});
gulp.task('default', function(callback) {
runSequence('build', 'watch', callback);
});
$ gulp build > will just run build the once and then exit.
$ gulp watch > will start watching (ctrl-c to exit).
$ gulp > will execute build and after that's complete it will run watch (ctrl-c to exit).
Note: I'm using the gulp-sequence plug to ensure that when running $ gulp the build will complete before the watch begins.

Answer 3

gulp.watch returns a FSWatcher object, which has a .close() method you can call to cancel the watch task:
var watchStream = gulp.watch(
src,
{ignoreInitial: true},
myGulpTask)
.on("change", function (triggerFileName) {
watchStream.close();
});
ignoreInitial = true prevents the task from running when the watcher starts. watchStream.close() will cancel the watcher, but the task will run once. So all in all, you get one task run.
This is with Gulp 4.