is-map

What is is-map?

The `is-map` npm package is a utility library designed to provide a simple and efficient way to check if a given value is a Map object. It is particularly useful in scenarios where type-checking is necessary to ensure that operations on map-like structures are performed safely and correctly.

What are is-map's main functionalities?

Type Checking for Map Objects

This feature allows developers to check if a given value is an instance of a Map. It is particularly useful for validating inputs or ensuring that certain operations are only performed on Map objects. The code sample demonstrates how to use `is-map` to distinguish between Map objects and regular JavaScript objects.

const isMap = require('is-map');

console.log(isMap(new Map())); // true
console.log(isMap({})); // false

Other packages similar to is-map

is

The `is` package offers a comprehensive set of type-checking utilities, including the ability to check if a value is a Map. Compared to `is-map`, `is` provides a broader range of type checks, making it a more versatile choice for projects that require extensive type validation.

lodash.ismap

Part of the Lodash library, `lodash.ismap` offers functionality similar to `is-map` by providing a method to check if a value is classified as a Map object. While `is-map` focuses solely on Map type checking, `lodash.ismap` benefits from being part of the larger Lodash ecosystem, which includes a wide array of utility functions for different data types.

README

is-map

Is this value a JS Map? This module works cross-realm/iframe, and despite ES6 @@toStringTag.

Example

var isMap = require('is-map');
assert(!isMap(function () {}));
assert(!isMap(null));
assert(!isMap(function* () { yield 42; return Infinity; });
assert(!isMap(Symbol('foo')));
assert(!isMap(1n));
assert(!isMap(Object(1n)));

assert(!isMap(new Set()));
assert(!isMap(new WeakSet()));
assert(!isMap(new WeakMap()));

assert(isMap(new Map()));

class MyMap extends Map {}
assert(isMap(new MyMap()));

Tests

Simply clone the repo, npm install, and run npm test

Changelog

v2.0.3 - 2024-03-08

Commits

• [actions] reuse common workflows ce10d0f
• [meta] use npmignore to autogenerate an npmignore file e07e23a
• add types cd13cfb
• [actions] use node/install instead of node/run; use codecov action 1e055f9
• [Dev Deps] update eslint, @ljharb/eslint-config, object-inspect, safe-publish-latest, tape 12d125e
• [Dev Deps] update eslint, @ljharb/eslint-config, aud, auto-changelog, es5-shim, object-inspect, tape adfb18e
• [actions] remove redundant finisher c5511b7
• [Dev Deps] update @ljharb/eslint-config, aud, es6-shim, npmignore, object-inspect, tape b2c7d67
• [actions] update rebase action to use reusable workflow bbad644
• [actions] update codecov uploader 8f57f98
• [Dev Deps] update eslint, @ljharb/eslint-config, auto-changelog, es5-shim, object-inspect, tape d330ff4
• [Dev Deps] update eslint, @ljharb/eslint-config, aud, object-inspect, tape 454e31c
• [Dev Deps] update eslint, @ljharb/eslint-config, es5-shim, tape b43283d
• [readme] add actions and codecov badges 0fc119e
• [Dev Deps] update eslint, object-inspect e2311f8
• [meta] add missing engines.node 9bddaf2
• [meta] use prepublishOnly script for npm 7+ d3b7661
• [Dev Deps] update safe-publish-latest 00d7b69
• [meta] add sideEffects flag bab4457