Run package's gulp task within my gulp task - gulp

Question

Is there a way to run a packages gulp task from within my gulp task? Here's my file structure:
Root
|
|-- Gulpfile.js (task: get-files)
|
|-- node_modules
|
|-- packageA
|
|-- gulpfile.js (task: compile-custom)
I want to run the compile-custom task from packageA from within my get-files task in my own gulpfile. Ideally, I could also get a callback from the compile-custom task to know when it is complete.

Answer 1

I would advise against running a task from another gulpfile as you want, especially from a node_modules package. A reason to not wanting to do so is due to the fact that the package can change/update and then break your code because of it.
Preferably you should just copy the gulpfile task you want into either your gulpfile and incorporate it into your project or just create a new file where you can easily distinguish that it is something separate from your gulpfile and just call it by requiring it in your own gulfile just like you would any other package and/or JS function. With either of these options do not forget to install the dependencies into your package.json files and then run npm install.
Note: To run a gulp task from within a gulp task you can use
gulp.start('taskname')
Although the following should be used only if completely necessary. In addition will be deprecated in the newer version of Gulp v4 (refer to this). The way to call a task is through just creating a function as mentioned above and calling that function in your gulpfile.
Example of gulp function calling:
var someFile = require('./someFile.js');
gulp.task('my-custom-task', function () {
someFile.doSomething('foo', 'bar');
});
If your function does something asynchronously, it should call a callback at the end, so gulp is able to know when it’s done:
var someFile = require('./someFile.js');
gulp.task('my-custom-task', function (callback) {
someFile.doSomething('foo', 'bar', callback);
});