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/isMap.md.
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    isMap es-toolkit

    Checks if a value is a Map.

    const result = isMap(value);

    Usage

    isMap(value)

    Use isMap when you want to check if a value is a Map instance. It uses the instanceof operator to check if it's a Map.

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

// Map instance
const map = new Map([['key', 'value']]);
console.log(isMap(map)); // true

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

    It can also be used as a type guard in TypeScript.

    function processValue(value: unknown) {
  if (isMap(value)) {
    // Now value is narrowed to Map<any, any> type
    console.log(value.size);
    value.set('new-key', 'new-value');
  }
}

    Parameters

    valueunknownrequired

    The value to check if it's a Map.

    Returns

    Returns true if the value is a Map, false otherwise.

    value is Map<any, 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.