Symbol: basics

Symbol

Symbol lives in the global scope

const actual = someNamespace.Symbol; assert.equal(actual, Symbol);

every Symbol() is unique

const sym1 = Symbol(); const sym2 = sym1; assert.notEqual(sym1, sym2);

every Symbol() is unique, also with the same parameter

var sym1 = Symbol('foo'); var sym1 = Symbol('foo'); assert.notEqual(sym1, sym2);

typeof Symbol() returns "symbol"

const theType = typeof Symbol; assert.equal(theType, 'symbol');

new Symbol() throws an exception, to prevent creation of Symbol wrapper objects

function fn() { Symbol(); } assert.throws(fn);

Related Katas

Symbol

• basics
• Symbol.for()
• Symbol.keyFor()

Difficulty Level

INTERMEDIATE

First Published

5 May 2015

Stats

5 tests to solve