For AI agents: the complete documentation index is available at /llms.txt, the full documentation bundle is available at /llms-full.txt, and this page is available as Markdown at /reference/predicate/isWeakMap.md.
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    isWeakMap es-toolkit

    Checks if a given value is a WeakMap instance.

    const result = isWeakMap(value);

    Usage

    isWeakMap(value)

    Use isWeakMap when you want to check if a value is a WeakMap instance. WeakMap is a key-value store with weak references to objects as keys, useful for preventing memory leaks.

    import { isWeakMap } from 'es-toolkit/predicate';

// WeakMap instances
const weakMap1 = new WeakMap();
const weakMap2 = new WeakMap([[{}, 'value']]);

console.log(isWeakMap(weakMap1)); // true
console.log(isWeakMap(weakMap2)); // true

// Non-WeakMap values
console.log(isWeakMap(new Map())); // false
console.log(isWeakMap(new Set())); // false
console.log(isWeakMap(new WeakSet())); // false
console.log(isWeakMap({})); // false
console.log(isWeakMap([])); // false
console.log(isWeakMap(null)); // false
console.log(isWeakMap(undefined)); // false

    Parameters

    valueunknownrequired

    The value to check if it's a WeakMap instance.

    Returns

    Returns true if the value is a WeakMap instance, false otherwise.

    value is WeakMap<WeakKey, any>
    Source: es-toolkit

    Re-exported verbatim from es-toolkit. Implementation, edge cases, and performance behavior are owned upstream. This page mirrors the documentation at the pinned version; the linked source is authoritative.