fix: listOf now returns List.of<T> (#144)

Author: patrickmichalina

src/list/list.factory.spec.ts

@@ -0,0 +1,32 @@
+import { listFrom, listOf } from './list.factory'
+
+describe('List Factory', () => {
+  describe(listFrom.name, () => {
+    it('should', () => {
+      const sut = listFrom([1, 2]).filter(a => a > 1)
+
+      expect(sut.toArray()).toEqual([2])
+    })
+
+    it('should handle undefined', () => {
+      const sut = listFrom<number>().filter(a => a > 1)
+
+      expect(sut.toArray()).toEqual([])
+    })
+  })
+
+  describe(listOf.name, () => {
+    it('should handle nominal', () => {
+      const sut = listOf(1, 2).filter(a => a > 1)
+
+      expect(sut.toArray()).toEqual([2])
+    })
+
+    it('should handle undefined', () => {
+      const sut = listOf<number>().filter(a => a > 1)
+
+      expect(sut.toArray()).toEqual([])
+    })
+  })
+})
+

src/list/list.factory.ts

@@ -1,17 +1,9 @@
 import { List } from './list'
 
 export function listOf<T>(...args: T[]) {
-  return List.of(args)
+  return List.of<T>(...args)
 }
 
-// export function listFrom<T>(value?: T) {
-//   return List.from<T>()
-// }
-
-// export function none<T>() {
-//   return Maybe.none<T>()
-// }
-
-// export function some<T>(value: T) {
-//   return maybe(value)
-// }
+export function listFrom<T>(value?: Iterable<T>) {
+  return List.from<T>(value)
+}

src/list/list.ts

@@ -30,10 +30,12 @@ export class List<T> {
     }, args.length)
   }
 
-  public static from<T>(iterable: Iterable<T>): List<T> {
-    return new List(function* () {
-      yield* iterable as any
-    } as any, (iterable as any).length)
+  public static from<T>(iterable?: Iterable<T>): List<T> {
+    return iterable
+      ? new List(function* () {
+        yield* iterable as any
+      } as any, (iterable as any).length)
+      : List.empty()
   }
 
   public static range(start: number, end: number, step = 1): List<number> {