ECMA6符号原语

Question

Currently i started working with JS ECMA6 for my personal web app, but I am not sure about usage of Symbols ie how can I make use of it?

I believe, they are tokens that serve as unique IDs. But I am not sure about its usage in web app development.

I am currently new to this standard, please provide your suggestions on it.

Answer 1

Symbols enable access control for object state. Symbols allow properties to be keyed by either string (as in ES5) or symbol. Symbols are a new primitive type. Optional description parameter used in debugging - but is not part of identity. Symbols are unique (like gensym), but not private since they are exposed via reflection features like Object.getOwnPropertySymbols.

var MyClass = (function() {

  // module scoped symbol
  var key = Symbol("key");

  function MyClass(privateData) {
    this[key] = privateData;
  }

  MyClass.prototype = {
    doStuff: function() {
      ... this[key] ...
    }
  };

  return MyClass;
})();

var c = new MyClass("hello")
c["key"] === undefined

It can be referred here . Here are few more links with nicely explained examples.(As already mentioned in comments section.)

• https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol
• http://www.2ality.com/2014/12/es6-symbols.html