problem with function at fields

test/swapi.spec.ts

@@ -0,0 +1,77 @@
+import { makeFromRecipe, makeFromFunction } from "../src/parser";
+import { expect } from "chai";
+
+const rawPlanet = {
+    name: 'Tatooine',
+    rotationPeriod: '23',
+    orbitalPeriod: '304',
+    diameter: '10465',
+    climate: 'arid',
+    gravity: '1 standard',
+    terrain: 'desert',
+    surfaceWater: '1',
+    population: '200000',
+    residents: [
+        'https://swapi.co/api/people/1/',
+        'https://swapi.co/api/people/2/',
+        'https://swapi.co/api/people/4/',
+        'https://swapi.co/api/people/6/',
+        'https://swapi.co/api/people/7/',
+        'https://swapi.co/api/people/8/',
+        'https://swapi.co/api/people/9/',
+        'https://swapi.co/api/people/11/',
+        'https://swapi.co/api/people/43/',
+        'https://swapi.co/api/people/62/'
+    ],
+    films: [
+        'https://swapi.co/api/films/5/',
+        'https://swapi.co/api/films/4/',
+        'https://swapi.co/api/films/6/',
+        'https://swapi.co/api/films/3/',
+        'https://swapi.co/api/films/1/'
+    ],
+    created: '2014-12-09T13:50:49.641000Z',
+    edited: '2014-12-21T20:48:04.175778Z',
+    url: 'https://swapi.co/api/planets/1/'
+};
+
+
+export class Planet {
+    name: string//"Tatooine"
+    rotationPeriod: number//"23"
+    orbitalPeriod: number//"304"
+    diameter: number//"10465"
+    climate: string//"arid"
+    gravity: string//"1 standard"
+    terrain: string//"desert"
+    surfaceWater: number//"1"
+    population: number//"200000"
+    residents: Array<string>
+    films: Array<string>
+    created: Date//"2014-12-09T13:50:49.641000Z"
+    edited: Date//"2014-12-21T20:48:04.175778Z"
+    url: string//"https://swapi.co/api/planets/1/"
+}
+
+const planetParser = makeFromRecipe({
+    target: Planet,
+    nestedTargets: {
+        rotationPeriod: makeFromFunction((it: string) => parseInt(it)),
+        orbitalPeriod: makeFromFunction((it: string) => parseInt(it)),
+        diameter: makeFromFunction((it: string) => parseInt(it)),
+        surfaceWater: makeFromFunction((it: string) => parseInt(it)),
+        population: makeFromFunction((it: string) => parseInt(it)),
+        created: makeFromFunction((it: string) => new Date(it)),
+        edited: makeFromFunction((it: string) => new Date(it)),
+    }
+})
+
+describe("Swapi", () => {
+    it("Get Planet", () => {
+        const planet = planetParser(rawPlanet)
+        expect(planet).to.instanceof(Planet)
+        expect(typeof planet.name).to.equals("string")
+        expect(typeof planet.population).to.equal("number")
+        expect(planet.created).to.instanceof(Date)
+    })
+})