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// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
import { assertEquals } from "../assert/mod.ts";import { groupBy } from "./group_by.ts";
function groupByTest<T>(  input: [Array<T>, (el: T) => PropertyKey],  expected: { [x: string]: Array<T> },  message?: string,) {  const actual = groupBy(...input);  assertEquals(actual, expected, message);}
Deno.test({  name: "[collections/groupBy] no mutation",  fn() {    const arrayA = [1.1, 4.2, 4.5];    groupBy(arrayA, () => "test");
    assertEquals(arrayA, [1.1, 4.2, 4.5]);  },});
Deno.test({  name: "[collections/groupBy] empty input",  fn() {    groupByTest(      [[], () => "a"],      {},    );  },});
Deno.test({  name: "[collections/groupBy] constant key",  fn() {    groupByTest(      [[1, 3, 5, 6], () => "a"],      { a: [1, 3, 5, 6] },    );  },});Deno.test({  name: "[collections/groupBy] non-string key",  fn() {    groupByTest(      [        [          { number: 1, name: "a" },          { number: 1, name: "b" },          { number: 2, name: "c" },          { number: 3, name: "d" },        ],        ({ number }) => number,      ],      {        1: [{ number: 1, name: "a" }, { number: 1, name: "b" }],        2: [{ number: 2, name: "c" }],        3: [{ number: 3, name: "d" }],      },    );  },});
Deno.test({  name: "[collections/groupBy] empty key",  fn() {    groupByTest(      [        ["Foo", "b"],        (it) => it.charAt(1),      ],      {        "o": ["Foo"],        "": ["b"],      },    );  },});
Deno.test({  name: "[collections/groupBy] groups",  fn() {    groupByTest(      [        ["Anna", "Marija", "Karl", "Arnold", "Martha"],        (it) => it.charAt(0),      ],      {        "A": ["Anna", "Arnold"],        "M": ["Marija", "Martha"],        "K": ["Karl"],      },    );    groupByTest(      [        [1.2, 2, 2.3, 6.3, 6.9, 6],        (it) => Math.floor(it).toString(),      ],      {        "1": [1.2],        "2": [2, 2.3],        "6": [6.3, 6.9, 6],      },    );  },});
Deno.test({  name: "[collections/groupBy] callback index",  fn() {    const actual = groupBy(      ["a", "b", "c", "d"],      (_, i) => i % 2 === 0 ? "even" : "odd",    );
    const expected = { even: ["a", "c"], odd: ["b", "d"] };
    assertEquals(actual, expected);  },});
Deno.test({  name: "[collections/groupBy] iterable input",  fn() {    function* count(): Generator<number, void> {      for (let i = 0; i < 5; i += 1) yield i;    }
    const actual = groupBy(count(), (n) => n % 2 === 0 ? "even" : "odd");    const expected = { even: [0, 2, 4], odd: [1, 3] };
    assertEquals(actual, expected);  },});