Add functions for helper functions

- Move `identity`, our only current helper function
- Add noop function
  - Can take any number of arguments, or expect any type as output.

src/functions.ts

@@ -0,0 +1,17 @@
+/**
+ * Returns the same value
+ * @param value
+ * @returns {T}
+ */
+export function identity<T>(value: T): T {
+    return value;
+}
+
+/**
+ * A type- and argument-agnostic function that returns null.
+ * @param args
+ * @returns {any}
+ */
+export function noop(...args: any[]): any {
+    return null;
+}

src/index.ts

@@ -3,8 +3,8 @@
  */
 export import collections = require("./collections");
 export import Either = require("./either");
+export import functions = require("./functions");
 export import Handle = require("./handle");
-export import identity = require("./identity");
 export import lists = require("./lists");
 export import Map = require("./map");
 export import Optional = require("./optional");

test/functions_test.ts

@@ -0,0 +1,29 @@
+import chai = require("chai");
+import tsutil = require("../src/index");
+
+var functions = tsutil.functions;
+var assert = chai.assert;
+
+suite("functions", () => {
+    suite("identity", () => {
+        test("should return the same value", () => {
+            var value = {};
+            assert.equal(value, functions.identity(value));
+        });
+    });
+
+    suite("noop", () => {
+        test("can be called with no arguments", () => {
+            assert.isNull(functions.noop());
+        });
+
+        test("can be called with two arguments", () => {
+            assert.isNull(functions.noop({}, {}));
+        });
+
+        test("can be called for any expected return type", () => {
+            var result: { fake_type: number } = functions.noop();
+            assert.isNull(result);
+        });
+    });
+});