js_interop/test/map_test.dart

// Copyright (c) 2026, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

import 'dart:js_interop';

import 'package:js_interop/js_interop.dart';
import 'package:test/test.dart';

void main() {
  late JSMap<JSNumber, JSString> map;
  setUp(() {
    map = JSMap(
      [
        [1.toJS, 'one'.toJS].toJS,
        [2.toJS, 'two'.toJS].toJS,
      ].toJS,
    );
  });

  test('constructor with no arguments returns an empty map', () {
    final map = JSMap();
    expect(map.size, equals(0));
    expect(map.keys.toDartIterable, isEmpty);
    expect(map.values.toDartIterable, isEmpty);
  });

  test('size returns the size of the map', () => expect(map.size, equals(2)));

  test('has returns whether the map has a key', () {
    expect(map.has(1.toJS), isTrue);
    expect(map.has(3.toJS), isFalse);
  });

  test('clear empties a map', () {
    map.clear();
    expect(map.size, equals(0));
    expect(map.keys.toDartIterable, isEmpty);
    expect(map.values.toDartIterable, isEmpty);
  });

  group('delete', () {
    test('removes a matching element from the map', () {
      expect(map.delete(1.toJS), isTrue);
      expect(map.has(1.toJS), isFalse);
      expect(map.size, equals(1));
    });

    test('ignores a non-matching element', () {
      expect(map.delete(3.toJS), isFalse);
      expect(map.size, equals(2));
    });
  });

  test('[] returns an element if the map contains it', () {
    expect(map[1.toJS], equals('one'.toJS));
    expect(map[3.toJS], isNull);
  });

  test('[]= adds an element to the map', () {
    map[3.toJS] = 'three'.toJS;
    expect(map.size, equals(3));
    expect(map[3.toJS], equals('three'.toJS));
  });

  test("keys returns the map's keys", () {
    expect(map.keys.toDartIterable, equals([1.toJS, 2.toJS]));
  });

  test("values returns the map's values", () {
    expect(map.values.toDartIterable, equals(['one'.toJS, 'two'.toJS]));
  });

  test('JSMap.toDart contains the expected values', () {
    final map = JSMap(
      [
        [1.toJS, 'one'.toJS].toJS,
        [double.nan.toJS, 'NaN'.toJS].toJS,
      ].toJS,
    ).toDart;
    expect(map.length, equals(2));
    expect(map, containsPair(1.toJS, 'one'.toJS));
    expect(map, containsPair(double.nan.toJS, 'NaN'.toJS));
  });

  test('JSMap.toDart handles null keys and values', () {
    final nullableMap = JSMap<JSNumber?, JSString?>(
      [
        [null, 'nullKey'.toJS].toJS,
        [1.toJS, null].toJS,
      ].toJS,
    ).toDart;
    expect(nullableMap, equals({null: 'nullKey'.toJS, 1.toJS: null}));
  });

  group('Map.toJS', () {
    test('contains the expected values', () {
      final map = {1.toJS: 'one'.toJS, 1.5.toJS: 'one and a half'.toJS}.toJS;
      expect(map.size, equals(2));
      expect(map[1.toJS], equals('one'.toJS));
      expect(map[1.5.toJS], equals('one and a half'.toJS));
    });

    test('uses later values for collisions', () {
      final dartMap = {
        double.nan.toJS: 'NaN 1'.toJS,
        double.nan.toJS: 'NaN 2'.toJS,
        double.nan.toJS: 'NaN 3'.toJS,
      };
      expect(dartMap.length, equals(3));
      final map = dartMap.toJS;
      expect(map.size, equals(1));
      expect(map[double.nan.toJS], equals('NaN 3'.toJS));
    });
  });
}