Does grunt silent errors in (bluebird) promises? - node.js

Question

I have a npm module which has main() function as its starting point.
Now, lets say I throw an Error immediently in that main() as shown below:
function main() {
throw new Error("An error!");
}
And then execute it with node my-app-that-launchers-main.js then obviously, the error is thrown and I get a stacktrace.
If I write a grunt task for this:
var mynpm = require("mynpm");
module.exports = function(grunt) {
grunt.registerTask("build",function() {
mynpm.build();
});
}
And execute it via Grunt, then it fails. The error is thrown and grunt fails, as expected.
However, if I wrap this throw inside a Bluebird Promise:
function main() {
Promise.try(function(resolve) {
throw new Error("An error!");
} ).catch(function() {
console.log("error");
} ).finally(function() {
console.log("finally");
});
}
And run it via node then I see that the catch function is invoked. As expected.
However, if I run the same code via Grunt's registertask, everything becomes dead silent. Nor the catch or the finally is called.
What could be causing this. It seems like Grunt hijacks errors are thrown.
Its a super easy to reproduce this, yet I am so puzzled about why.
Does Grunt hijack errors that are thrown, somehow, so not even the Promise's catch and finally functions gets invoked?
How can the execution and the error handling be so different if its executed manually, compared with if Grunt executes the code?

Answer 1

You are looking to define an async task. This can be done using this.async():
grunt.registerTask("build",function() {
// Tell Grunt this task is asynchronous.
var done = this.async();
mynpm.build();
});
More information about async tasks here : https://gruntjs.com/api/inside-tasks