like-a-symbol

An alternative to EcmaScript 6 Symbol that can be chained with strings and used with JSON.stringify(...);

Reason

Symbol() function in JavaScript has some features that can be annoying:

const s = Symbol('S');
console.log('I like the symbol ' + s);

// Throws: Uncaught TypeError: Cannot convert a Symbol value to a string

const vegetable = {label: 'pear', type: Symbol('pear')};
console.log(JSON.stringify(vegetable));
// Outputs: "{"label":"pear"}", type field is lost.

Installation

npm install --save like-a-symbol

Usage

<script src="https://unpkg.com/like-a-symbol@1.0.0/src/index.js"></script>
<script>
  const pear = LikeASymbol('pear');
</script>

or

import { LikeASymbol } from 'like-a-symbol';
const pear = LikeASymbol('pear');

Syntax

LikeASymbol([description])

Parameters: description: String | optional

Optional, string. A description of the symbol which can be used for debugging.

Description

You can use LikeASymbol to emulate part of the behavior of the ES6 Symbol() avoiding exceptions when the symbol is put inside a string for debug reasons.

In addition Symbols are not serialized with JSON.stringify(...), whereas with LikeASymbol its string representation will be serialized and can be parsed back using LikeASymbol.fromString(value) function.

const s1 = LikeASymbol();
const s2 = LikeASymbol('foo');

LikeASymbol('foo') === LikeASymbol('foo'); // false
console.log('Symbol: ' + LikeASymbol('Foo')); // Symbol: LikeASymbol(Foo)
LikeASymbol('Foo').toString() === 'LikeASymbol(Foo)'; // true

JSON.stringify({ label: 'pear', type: LikeASymbol('pear') }); // {"label":"pear","type":"LikeASymbol(pear)"}

Methods

LikeASymbol.fromString(value)

Returns LikeASymbol instance from a valid string representation.

Throws a SyntaxError if the given string value is not a valid representation of a LikeASymbol instance.

LikeASymbol.isParsable(value)

Returns true if value is a parsable string representation of the symbol. Returns false otherwise.

Keep in mind

Keep in mind that LikeASymbol is not a Symbol, so function like Object.getOwnPropertySymbols() will not return any property defined with LikeASymbol. Also LikeASymbol('foo') == 'LikeASymbol(foo)' will return true.

Symbol() is designed to be unique and not comparable with strings, whereas LikeASymbol is designed to be loosely linked to its string representation.

Symbol.for(key) and Symbol.keyFor(symbol) are not ported to LikeASymbol. If you need them, you probably want to use the ECS6 Symbol, and not LikeASymbol.

If you look for a Symbol replacement that works in older browers, google "Symbol polyfill".