Symbol.prototype.description

An ECMAScript spec-compliant Symbol.prototype.description shim. Invoke its "shim" method to shim Symbol.prototype.description if it is unavailable. Note: Symbol#description requires a true ES6 environment, specifically one with native Symbols.

This package implements the es-shim API interface. It works in an ES6-supported environment and complies with the spec.

Most common usage:

var description = require('symbol.prototype.description');

assert(description(Symbol('foo')) === 'foo');
assert(description(Symbol()) === undefined);
assert(description(Symbol(undefined)) === undefined);
assert(description(Symbol(null)) === 'null');

// note: this should be the empty string, but in many engines,
// it is impossible to distinguish Symbol() and Symbol('')
// without globally replacing `Symbol`
assert(description(Symbol('')) === undefined);

if (!Symbol.prototype.description) {
	description.shim();
}

assert(description(Symbol('foo')) === Symbol('foo').description);
assert(description(Symbol()) === Symbol().description);
assert(description(Symbol(undefined)) === Symbol(undefined).description);
assert(description(Symbol(null)) === Symbol(null).description);

assert(Symbol('').description === ''); // this works fine!

Tests

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

Current Tags

• 1.0.2                                ...           latest (6 years ago)

1 Versions

• 1.0.2                                ...           6 years ago