Improved "first" typing for tuples

package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "tk-functional",
-  "version": "0.1.5",
+  "version": "0.2.3",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {

package.json

@@ -1,6 +1,6 @@
 {
   "name": "tk-functional",
-  "version": "0.2.2",
+  "version": "0.2.3",
   "description": "Typescript/Javascript helpers for functional-style programming",
   "source": "src/index.ts",
   "main": "dist/tk-functional.umd.js",

src/index.test.ts

@@ -1,4 +1,4 @@
-import { always, and, at, attr, bool, cmp, first, fmap, identity, is, isinstance, last, never, nn, nnu, nop, not, nu, or, partial, pipe } from "./index";
+import { always, and, at, attr, bool, cmp, first, fmap, identity, is, isinstance, last, never, nn, nnu, nop, not, nu, or, partial, pipe, second, third } from "./index";
 
 describe(nop, () => {
   it("does nothing", () => {
@@ -158,6 +158,22 @@ describe(first, () => {
   });
 });
 
+describe(second, () => {
+  it("gets the second item in an array", () => {
+    expect(second([1, 4, 8])).toBe(4);
+    expect(second([1])).toBeUndefined();
+    expect(second([])).toBeUndefined();
+  });
+});
+
+describe(third, () => {
+  it("gets the third item in an array", () => {
+    expect(third([1, 4, 8])).toBe(8);
+    expect(third([1, 4])).toBeUndefined();
+    expect(third([])).toBeUndefined();
+  });
+});
+
 describe(last, () => {
   it("gets the last item in an array", () => {
     expect(last([1, 4, 8])).toBe(8);

src/index.ts

@@ -125,7 +125,17 @@ export function at<T>(idx: number): (array: ReadonlyArray<T>) => T | undefined {
 /**
  * Array first item getter
  */
-export const first: <T>(array: ReadonlyArray<T>) => T | undefined = at(0);
+export const first: <T extends ReadonlyArray<any>>(array: T) => T[0] | undefined = at(0);
+
+/**
+ * Array second item getter
+ */
+export const second: <T extends ReadonlyArray<any>>(array: T) => T[1] | undefined = at(1);
+
+/**
+ * Array third item getter
+ */
+export const third: <T extends ReadonlyArray<any>>(array: T) => T[2] | undefined = at(2);
 
 /**
  * Array last item getter