has-symbols

What is has-symbols?

The has-symbols npm package is used to determine if the JavaScript environment has native support for ES6/ES2015 symbols. Symbols are a new primitive type introduced in ES6 that enable the creation of unique identifiers for object properties. The has-symbols package provides a simple way to check for symbol support, which is useful for library authors who want to create code that is compatible with both modern and older environments.

What are has-symbols's main functionalities?

Check for native Symbol support

This feature allows you to check if the current JavaScript environment supports ES6 symbols natively. The function `hasSymbols()` returns a boolean indicating the presence of native symbol support.

var hasSymbols = require('has-symbols');

if (hasSymbols()) {
  console.log('Environment has native Symbol support');
} else {
  console.log('Environment does not have native Symbol support');
}

Check for well-known symbols

This feature allows you to check for the presence of specific well-known symbols like `Symbol.hasInstance`, `Symbol.iterator`, etc. The function `hasSymbols(shim)` takes a string argument representing the well-known symbol and returns a boolean indicating its presence.

var hasSymbols = require('has-symbols');

if (hasSymbols('hasInstance')) {
  console.log('Environment has Symbol.hasInstance');
} else {
  console.log('Environment does not have Symbol.hasInstance');
}

Other packages similar to has-symbols

es-abstract

The es-abstract package provides utility functions for ECMAScript language abstract operations. It includes checks for symbol support similar to has-symbols but goes beyond that by offering a wide range of ECMAScript compliance-related utilities.

is-symbol

The is-symbol package is used to check if a value is an ES6 Symbol or not. While has-symbols checks for the existence of Symbol support in the environment, is-symbol is used to verify if a given value is of the Symbol type.

README

has-symbols

Determine if the JS environment has Symbol support. Supports spec, or shams.

Example

var hasSymbols = require('has-symbols');

hasSymbols() === true; // if the environment has native Symbol support. Not polyfillable, not forgeable.

var hasSymbolsKinda = require('has-symbols/shams');
hasSymbolsKinda() === true; // if the environment has a Symbol sham that mostly follows the spec.

Supported Symbol shams

• get-own-property-symbols npm | github
• core-js npm | github

Tests

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

Changelog

v1.1.0 - 2024-12-02

Commits

• [actions] update workflows 548c0bf
• [actions] further shard; update action deps bec56bb
• [meta] use npmignore to autogenerate an npmignore file ac81032
• [New] add types 6469cbf
• [actions] update rebase action to use reusable workflow 9c9d4d0
• [Dev Deps] update eslint, @ljharb/eslint-config, aud, tape adb5887
• [Dev Deps] update @ljharb/eslint-config, aud, tape 13ec198
• [Dev Deps] update auto-changelog, core-js, tape 941be52
• [Tests] replace aud with npm audit 74f49e9
• [Dev Deps] update npmignore 9c0ac04
• [Dev Deps] add missing peer dep 52337a5