@zerodep/is-weakmap

A simple, performant utility to determine if a value is a Weak Map.

Full documentation is available at the zerodep.app page.

Signature

1declare const isWeakmap: (value: unknown) => boolean;

Examples

All @zerodep packages support both ESM and CJS formats, each complete with Typescript typings.

1// ESM
2import { isWeakmap } from '@zerodep/is-weakmap';
3
4// CJS
5// CJS
6const { isWeakmap } = require('@zerodep/is-weakmap');

1// Arrays
2isWeakmap([]); // false
3isWeakmap([1, 2, 3]); // false
4isWeakmap(['a', 'b', 'c']); // false
5
6// BigInts
7isWeakmap(42n); // false
8isWeakmap(0n); // false
9isWeakmap(-0n); // false
10isWeakmap(-42n); // false
11
12// Booleans
13isWeakmap(true); // false
14isWeakmap(false); // false
15
16// Class
17isWeakmap(
18  class SomeClass {
19    constructor() {}
20  }
21); // false
22
23// Dates
24isWeakmap(new Date()); // false
25isWeakmap(new Date('1970-01-01T12:00:00.000Z')); // false
26isWeakmap(new Date('2099-12-31')); // false
27
28// Empty
29isWeakmap(null); // false
30isWeakmap(undefined); // false
31
32// Errors
33isWeakmap(new Error('message')); // false
34isWeakmap(new AggregateError([new Error('err1'), new Error('err2')], 'message')); // false
35
36// Floats
37isWeakmap(3.14); // false
38isWeakmap(0.0); // false
39isWeakmap(-0.0); // false
40isWeakmap(-3.14); // false
41isWeakmap(Math.E); // false
42isWeakmap(Math.PI); // false
43isWeakmap(Number.MIN_VALUE); // false
44
45// Functions
46isWeakmap(() => 'function'); // false
47isWeakmap(async () => 'function'); // false
48
49// Generators
50isWeakmap(function* () {
51  yield 'a';
52}); // false
53isWeakmap(async function* () {
54  yield 'a';
55}); // false
56
57// Maps
58isWeakmap(new Map()); // false
59isWeakmap(new Map([['key1', 123]])); // false
60isWeakmap(new Map([['key1', 'value1']])); // false
61
62// Numbers
63isWeakmap(Number.POSITIVE_INFINITY); // false
64isWeakmap(Number.MAX_SAFE_INTEGER); // false
65isWeakmap(3e8); // false
66isWeakmap(42); // false
67isWeakmap(1); // false
68isWeakmap(0); // false
69isWeakmap(-0); // false
70isWeakmap(-1); // false
71isWeakmap(-42); // false
72isWeakmap(-3e8); // false
73isWeakmap(Number.MIN_SAFE_INTEGER); // false
74isWeakmap(Number.NEGATIVE_INFINITY); // false
75isWeakmap(Number.NaN); // false
76
77// POJOs
78isWeakmap({}); // false
79isWeakmap({ key: 'string' }); // false
80isWeakmap({ key: 123 }); // false
81
82// Promise
83isWeakmap(new Promise(() => {})); // false
84isWeakmap(new Promise.all([])); // false
85isWeakmap(new Promise.allSettled([])); // false
86isWeakmap(new Promise.race([])); // false
87isWeakmap(Promise.resolve()); // false
88
89// Regular Expression
90isWeakmap(/[regex]+/gi); // false
91isWeakmap(new RegExp('d', 'gi')); // false
92
93// Sets
94isWeakmap(new Set()); // false
95isWeakmap(new Set([1, 2, 3])); // false
96isWeakmap(new Set(['a', 'b', 'c'])); // false
97
98// Strings
99isWeakmap(''); // false
100isWeakmap('a longer string'); // false
101isWeakmap('1000n'); // false
102isWeakmap('3e8'); // false
103isWeakmap('42'); // false
104isWeakmap('3.14'); // false
105isWeakmap('0'); // false
106isWeakmap('-0'); // false
107isWeakmap('-3.14'); // false
108isWeakmap('-42'); // false
109isWeakmap('-3e8'); // false
110isWeakmap('-1000n'); // false
111
112// Symbols
113isWeakmap(Symbol()); // false
114isWeakmap(Symbol('name')); // false
115
116// This
117isWeakmap(this); // false
118isWeakmap(globalThis); // false
119
120// TypedArrays
121isWeakmap(new Int8Array(2)); // false
122isWeakmap(new Int16Array(2)); // false
123isWeakmap(new Int32Array(2)); // false
124isWeakmap(new Uint8Array(2)); // false
125isWeakmap(new Uint16Array(2)); // false
126isWeakmap(new Uint32Array(2)); // false
127isWeakmap(new Uint8ClampedArray(2)); // false
128
129isWeakmap(new BigInt64Array(2)); // false
130isWeakmap(new BigUint64Array(2)); // false
131
132isWeakmap(new Float32Array(2)); // false
133isWeakmap(new Float64Array(2)); // false
134
135isWeakmap(new SharedArrayBuffer(512)); // false
136
137// WeakMap and WeakSet
138isWeakmap(new WeakMap()); // true
139isWeakmap(new WeakSet()); // false

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ZeroDep Advantages

• Zero npm dependencies - completely eliminates all risk of supply-chain attacks, decreases node_modules folder size
• ESM & CJS - has both ecmascript modules and common javascript exports
• Tree Shakable - built to be fully tree shakable ensuring your packages are the smallest possible size
• Fully typed - typescript definitions are provided for every package for a better developer experience
• Semantically named - package and method names are easy to grok, remember, use, and read
• Documented - actually useful documentation with examples at zerodep.app
• Intelligently Packaged - multiple npm packages of different sizes available allowing a menu or a-la-carte composition of capabilities
• 100% Tested - all methods and packages are fully unit tested
• Predictably Versioned - semantically versioned for peace-of-mind upgrading, this includes changelogs
• MIT Licensed - permissively licensed for maximum usability