⚡️ Implement a custom done and waterfall static method for the `S…

…wiftPledge` class

CHANGELOG.md

@@ -5,6 +5,7 @@
 * Add some devtools functions for custom inspect formatting
 * Add `Pledge#getResolvedFunction()` method, which can be passed as an old-style callback
 * Fix some `Swift` methods not using the correct schedulers
+* Implement a custom `done` and `waterfall` static method for the `SwiftPledge` class
 
 ## 0.9.2 (2024-02-25)
 

lib/pledge.js

@@ -1382,20 +1382,49 @@ var Timeout = Fn.inherits('Pledge', function TimeoutPledge(executor, timeout, me
  *
  * @author   Jelle De Loecker <[email protected]>
  * @since    0.8.15
- * @version  0.8.15
+ * @version  0.9.3
  *
  * @param    {Function}   executor
  */
 const Swift = Fn.inherits(Pledge, function SwiftPledge(executor) {
-	this[EXECUTOR] = executor;
-	this[START_EXECUTOR](false);
+	if (executor != null) {
+		this[EXECUTOR] = executor;
+		this[START_EXECUTOR](false);
+	}
 });
 
 const SwiftObject = Object.create(Bound.Function);
 SwiftObject[Blast.flowPledgeClass] = Swift;
 SwiftObject[Blast.asyncScheduler] = Blast.callNow;
 Swift[FNC] = SwiftObject;
 
+/**
+ * Handle an old-style callback for a pledge or promise
+ *
+ * @author   Jelle De Loecker <[email protected]>
+ * @since    0.9.3
+ * @version  0.9.3
+ */
+Swift.setStatic(function done(value, callback) {
+
+	// Pass through falsy or non-object values
+	if (!value || typeof value != 'object') {
+		return callback(null, value);
+	}
+
+	// Pass non-thenables through
+	if (!value.then) {
+		return callback(null, value);
+	}
+
+	// See if we can rip the values out of Pledge instances
+	if (value[STATE] == RESOLVED) {
+		return callback(null, value[RESOLVED_VALUE]);
+	}
+
+	value.then(val => callback(null, val), callback);
+});
+
 /**
  * Do the given tasks in parallel
  *
@@ -1502,18 +1531,61 @@ Swift.setStatic(function execute(value) {
 	return value;
 });
 
+/**
+ * Do a single waterfall task
+ *
+ * @author   Jelle De Loecker <[email protected]>
+ * @since    0.9.3
+ * @version  0.9.3
+ */
+const doWaterfallTask = (pledge, tasks, index, max_index, previous_value) => {
+
+	let task = tasks[index],
+	    next_value;
+
+	if (typeof task == 'function') {
+		try {
+			next_value = task(previous_value);
+		} catch (err) {
+			return pledge.reject(err);
+		}
+	} else {
+		next_value = task;
+	}
+
+	Swift.done(next_value, (err, result) => {
+
+		if (err) {
+			return pledge.reject(err);
+		}
+
+		if (index == max_index) {
+			return pledge.resolve(result);
+		}
+
+		doWaterfallTask(pledge, tasks, index + 1, max_index, result);
+	});
+};
+
 /**
  * Perform a swift waterfall
  *
  * @author   Jelle De Loecker <[email protected]>
  * @since    0.8.15
- * @version  0.8.15
+ * @version  0.9.3
  *
  * @return   {SwiftPledge|Mixed}
  */
 Swift.setStatic(function waterfall(...tasks) {
-	let result = SwiftObject.waterfall(...tasks);
-	return Swift.execute(result);
+	let pledge = new Swift();
+
+	doWaterfallTask(pledge, tasks, 0, tasks.length - 1, null);
+
+	if (pledge[STATE] == RESOLVED) {
+		return pledge[RESOLVED_VALUE];
+	}
+
+	return pledge;
 });
 
 /**