feat: Add promise.asCallback method

promise/#/as-callback.js

@@ -0,0 +1,19 @@
+"use strict";
+
+var ensurePlainFunction = require("../../object/ensure-plain-function")
+  , ensureThenable      = require("../../object/ensure-thenable")
+  , microtaskDelay      = require("../../function/#/microtask-delay");
+
+module.exports = function (callback) {
+	ensureThenable(this);
+	ensurePlainFunction(callback);
+	// Rely on microtaskDelay to escape eventual error swallowing
+	this.then(
+		microtaskDelay.call(function (value) {
+			callback(null, value);
+		}),
+		microtaskDelay.call(function (reason) {
+			callback(reason);
+		})
+	);
+};

promise/#/index.js

@@ -0,0 +1,5 @@
+"use strict";
+
+module.exports = {
+	asCallback: require("./as-callback")
+};

promise/index.js

@@ -1,5 +1,6 @@
 "use strict";
 
 module.exports = {
-	lazy: require("./lazy")
+	"#": require("./#"),
+	"lazy": require("./lazy")
 };

test/promise/#/as-callback.js

@@ -0,0 +1,32 @@
+"use strict";
+
+module.exports = function (t, a) {
+	if (typeof Promise !== "function") return null;
+	return {
+		Success: function (d) {
+			t.call(
+				new Promise(function (resolve) {
+					resolve("foo");
+				}),
+				function (error, value) {
+					a(error, null);
+					a(value, "foo");
+					d();
+				}
+			);
+		},
+		Failure: function (d) {
+			var error = new Error("Rejection");
+			t.call(
+				new Promise(function (resolve, reject) {
+					reject(error);
+				}),
+				function (passedError, value) {
+					a(passedError, error);
+					a(value, undefined);
+					d();
+				}
+			);
+		}
+	};
+};

test/promise/.eslintrc.json

@@ -1,3 +1,3 @@
 {
-  "globals": { "setTimeout": true }
+  "globals": { "Promise": true, "setTimeout": true }
 }