isMap

Checks if a value is a Map.

const result = isMap(value);

Reference

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

• value (unknown): The value to check if it's a Map.

Returns

(value is Map<any, any>): Returns true if the value is a Map, false otherwise.