add getOrElse method to Option

CHANGELOG.md

@@ -17,6 +17,7 @@
 - **New Feature**
   - make Array<T> a HKT and deprecate `to`,`from` helper functions, fix #5 (@gcanti)
   - add `Traced` comonad (@bumbleblym)
+  - add `getOrElse` method to `Option` (@gcanti)
 - **Polish**
   - add tslint
 

package.json

@@ -10,7 +10,7 @@
   "jsnext:main": "lib-jsnext/index.js",
   "typings": "lib/index.d.ts",
   "scripts": {
-    "lint": "tslint src/**/*.ts",
+    "lint": "tslint src/**/*.ts test/**/*.ts",
     "test": "npm run lint && mocha -r ts-node/register test/*.ts",
     "build": "rm -rf lib/* && tsc && tsc -m es6 --outDir lib-jsnext"
   },

src/Option.ts

@@ -24,6 +24,7 @@ export interface Option<A> extends HKTOption<A> {
   alt(fa: Option<A>): Option<A>
   extend<B>(fy: Function1<Option<A>, B>): Option<B>
   fold<B>(n: Lazy<B>, s: Function1<A, B>): B
+  getOrElse(f: Lazy<A>): A
   concat(semigroup: Semigroup<A>, fy: Option<A>): Option<A>
   equals(setoid: Setoid<A>, fy: Option<A>): boolean
 }
@@ -63,6 +64,9 @@ export class None<A> implements Option<A> {
   fold<B>(n: Lazy<B>, s: Function1<A, B>): B {
     return n()
   }
+  getOrElse(f: Lazy<A>): A {
+    return f()
+  }
   concat(semigroup: Semigroup<A>, fy: Option<A>): Option<A> {
     return fy
   }
@@ -113,6 +117,9 @@ export class Some<A> implements Option<A> {
   fold<B>(n: Lazy<B>, s: Function1<A, B>): B {
     return s(this.value)
   }
+  getOrElse(f: Lazy<A>): A {
+    return this.value
+  }
   concat(semigroup: Semigroup<A>, fy: Option<A>): Option<A> {
     return fy.fold(() => this, y => new Some(semigroup.concat(this.value, y)))
   }

test/Arr.ts

@@ -70,15 +70,15 @@ describe('Arr', () => {
   })
 
   it('takeWhile', () => {
-    assert.deepEqual(arr.takeWhile((n) => n % 2 == 0, as), [2])
+    assert.deepEqual(arr.takeWhile((n) => n % 2 === 0, as), [2])
   })
 
   it('drop', () => {
     assert.deepEqual(arr.drop(2, as), [3])
   })
 
   it('dropWhile', () => {
-    assert.deepEqual(arr.dropWhile((n) => n % 2 == 0, as), [1, 3])
+    assert.deepEqual(arr.dropWhile((n) => n % 2 === 0, as), [1, 3])
   })
 
   it('init', () => {
@@ -129,5 +129,4 @@ describe('Arr', () => {
     assert.deepEqual(arr.sort(numberOrd, [3, 2, 1]), [1, 2, 3])
   })
 
-
 })

test/Option.ts

@@ -23,6 +23,11 @@ describe('Option', () => {
     assert.strictEqual(fold(f, g, some('abc')), 'some3')
   })
 
+  it('getOrElse', () => {
+    assert.strictEqual(some(1).getOrElse(() => 0), 1)
+    assert.strictEqual(none.getOrElse(() => 0), 0)
+  })
+
   it('equals', () => {
     assert.strictEqual(equals(setoidNumber, none, none), true)
     assert.strictEqual(equals(setoidNumber, none, some(1)), false)
@@ -51,7 +56,7 @@ describe('Option', () => {
   })
 
   it('getMonoid', () => {
-    const { concat } = getMonoid({ concat(x: number, y: number){ return x + y } })
+    const { concat } = getMonoid({ concat(x: number, y: number) { return x + y } })
     eq(concat(none, some(1)), some(1))
     eq(concat(some(2), none), some(2))
     eq(concat(some(2), some(1)), some(3))

test/Traced.ts

@@ -3,7 +3,7 @@ import { identity } from '../src/function'
 import { monoidSum } from '../src/Monoid'
 import {
   getComonad,
-  Traced,
+  Traced
 } from '../src/Traced'
 
 describe('Traced', () => {
@@ -68,7 +68,7 @@ describe('Traced', () => {
 
     assert.strictEqual(
       extract(extend(ea => extract(ea), t)),
-      extract(t),
+      extract(t)
     )
   })
 
@@ -81,7 +81,7 @@ describe('Traced', () => {
 
     assert.strictEqual(
       extract(extend(f , t)),
-      f(t),
+      f(t)
     )
   })
 })