async-recurse

Usage: asyncRecurse(obj, iterate[, options, callback])

var targetObject = JSON.parse(someJsonObject);

let iterate = (value, callback) => {
	setTimeout(() => {
		console.log('done with', value)
		return callback(null); // I can pass a truthy value here to error the iteration - which would prematurely end the traversal
	}, 100);
};

To use with a callback:

asyncRecurse(targetObject, iterate, options, (err) => {
	if (err) throw Err;

	//...
});

To use as an ES6 Promise, do not pass a fourth argument:

asyncRecurse(targetObject, worker, options)
.then(...)
.catch(...);

Or most simply:

asyncRecurse(targetObject, worker)
...

Basic behavior

If called as an ES6 Promise, then the worker can itself be a Promise. Regardless of whether Promises or callbacks are used, the worker can always be a function with the arguments value and callback. The worker's callback can take an error argument, which if truthy, will prematurely terminate the traversal in a similar fashion to how Promise.all will break the iteration if any Promise fails. If you choose to define your worker as a Promise, then you can reject from your worker to get the same behavior.

Options:

Name	Type	Default
includeLeaves	Boolean	true
includeBranches	Boolean	false
parallel	Boolean	true

If parallel is off, the work will be done serially - the next worker won't start until the previous finished. This walk is performed as a depth-first pre-order traversal and the order serialization will accord.

A branch is an Object or Array and a leaf is everything else (in other words if you're parsing from JSON a leaf must be a String, Number, Boolean, or null).

by Dillon Bostwick