index.test.ts

import test from "ava";
import {entries, filter, keys, map, values} from "./index";

test("map", t => {
    t.deepEqual(
        map({a: 1, b: 2}, value => value + 1),
        {a: 2, b: 3}
    );
    t.deepEqual(
        map({a: 1, b: 2}, (value, key) => (value * 2).toString(10) + key),
        {a: "2a", b: "4b"}
    );
});

test("filter", t => {
    const dictionary = {a: 1, b: 2, c: 3, d: 17, e: 24};
    t.deepEqual(
        filter(dictionary, value => value % 2 === 0),
        {b: 2, e: 24}
    );
    t.deepEqual(
        filter(dictionary, (value: number, key: string) => value % 2 === 1 && key !== "c"),
        {a: 1, d: 17}
    );
});

interface Furniture {
    readonly hatstand: number;
    readonly sofa: string;
}

test("keys", t => {
    const furniture: Furniture = {hatstand: 3, sofa: "comfy"};
    t.deepEqual(keys(furniture), ["hatstand", "sofa"]);
    const dictionary: Record<string, number> = {a: 1, b: 2};
    const dictionaryKeys: string[] = keys(dictionary);
    t.deepEqual(dictionaryKeys, ["a", "b"]);
});

test("values", t => {
    const furniture: Furniture = {hatstand: 3, sofa: "comfy"};
    t.deepEqual(values(furniture), [3, "comfy"]);
    const dictionary: Record<string, number> = {a: 1, b: 2};
    t.deepEqual(values(dictionary), [1, 2]);
});

test("entries", t => {
    const furniture: Furniture = {hatstand: 3, sofa: "comfy"};
    t.deepEqual(entries(furniture), [
        ["hatstand", 3],
        ["sofa", "comfy"]
    ]);
    const dictionary: Record<string, number> = {a: 1, b: 2};
    const dictionaryEntries: Array<[string, number]> = entries(dictionary);
    t.deepEqual(dictionaryEntries, [
        ["a", 1],
        ["b", 2]
    ]);
});