Integrate jest and add first test file (#51)

This sets up the first bit of test infrastructure to write and run unit tests on every PR

Related to #14 
Fixes #7

package.json

@@ -7,7 +7,8 @@
     "deploy": "./deploy.sh",
     "prettier": "prettier --write './**/*.ts' './**/*.tsx'",
     "lint": "eslint './**/*.ts' './**/*.tsx'",
-    "test": "npm run lint",
+    "jest": "jest",
+    "test": "tsc --noEmit && npm run lint && jest",
     "serve": "parcel index.html --open --no-autoinstall"
   },
   "browserslist": [
@@ -17,17 +18,33 @@
   "author": "",
   "license": "MIT",
   "devDependencies": {
+    "@types/jest": "^22.2.3",
+    "@types/pako": "1.0.0",
     "aphrodite": "2.1.0",
     "eslint": "^4.19.1",
     "eslint-plugin-prettier": "^2.6.0",
+    "jest": "^23.0.1",
+    "pako": "1.0.6",
     "parcel-bundler": "1.7.0",
     "preact": "8.2.7",
     "prettier": "^1.12.0",
     "regl": "1.3.1",
+    "ts-jest": "^22.4.6",
     "typescript": "2.8.1",
     "typescript-eslint-parser": "^14.0.0",
-    "uglify-es": "3.2.2",
-    "@types/pako": "1.0.0",
-    "pako": "1.0.6"
+    "uglify-es": "3.2.2"
+  },
+  "jest": {
+    "transform": {
+      "^.+\\.tsx?$": "ts-jest"
+    },
+    "testRegex": "\\.test\\.tsx?$",
+    "moduleFileExtensions": [
+      "ts",
+      "tsx",
+      "js",
+      "jsx",
+      "json"
+    ]
   }
 }

utils.test.ts

@@ -0,0 +1,66 @@
+import {
+  sortBy,
+  getOrInsert,
+  getOrElse,
+  getOrThrow,
+  itMap,
+  itForEach,
+  itReduce,
+  zeroPad,
+} from './utils'
+
+test('sortBy', () => {
+  const ls = ['a3', 'b2', 'c1', 'd4']
+  sortBy(ls, k => k.charCodeAt(1))
+  expect(ls).toEqual(['c1', 'b2', 'a3', 'd4'])
+})
+
+test('getOrInsert', () => {
+  const m = new Map<string, number>()
+  expect(getOrInsert(m, 'hello', k => k.length)).toBe(5)
+  expect(getOrInsert(m, 'hello', k => 2 * k.length)).toBe(5)
+  expect(getOrInsert(m, 'x', k => k.length)).toBe(1)
+  expect(m.get('hello')).toBe(5)
+  expect(m.get('x')).toBe(1)
+})
+
+test('getOrElse', () => {
+  const m = new Map<string, number>()
+  expect(getOrElse(m, 'hello', k => k.length)).toBe(5)
+  expect(getOrElse(m, 'hello', k => 2 * k.length)).toBe(10)
+  expect(getOrElse(m, 'x', k => k.length)).toBe(1)
+  expect(getOrElse(m, 'x', () => 3)).toBe(3)
+  expect(m.get('hello')).toBe(undefined)
+  expect(m.get('x')).toBe(undefined)
+})
+
+test('getOrThrow', () => {
+  const m = new Map<string, number>()
+  m.set('hello', 5)
+  expect(getOrThrow(m, 'hello')).toBe(5)
+  expect(() => getOrThrow(m, 'goodbye')).toThrow('Expected key goodbye')
+})
+
+test('itMap', () => {
+  const s = new Set<number>([1, 2, 3])
+  expect(new Set(itMap(s, v => v * v))).toEqual(new Set([1, 4, 9]))
+})
+
+test('itForEach', () => {
+  const s = new Set<number>([1, 2, 3])
+  const t = new Set()
+  itForEach(s, v => t.add(v * v))
+  expect(t).toEqual(new Set([1, 4, 9]))
+})
+
+test('itReduce', () => {
+  const s = new Set<number>([1, 2, 3])
+  expect(itReduce(s, (a, b) => a + b, 0)).toBe(6)
+})
+
+test('zeroPad', () => {
+  expect(zeroPad('1', 2)).toBe('01')
+  expect(zeroPad('1', 3)).toBe('001')
+  expect(zeroPad('1000', 3)).toBe('1000')
+  expect(zeroPad('FF', 4)).toBe('00FF')
+})

utils.ts

@@ -14,7 +14,7 @@ export function getOrInsert<K, V>(map: Map<K, V>, k: K, fallback: (k: K) => V):
   return map.get(k)!
 }
 
-export function getOrElse<K, V>(map: Map<K, V>, k: K, fallback: (k?: K) => V): V {
+export function getOrElse<K, V>(map: Map<K, V>, k: K, fallback: (k: K) => V): V {
   if (!map.has(k)) return fallback(k)
   return map.get(k)!
 }