Why does Crockford say not to use the new keyword if he advises us to use it for prototypal inheritance?

后端 未结 2 1796
不思量自难忘°
不思量自难忘° 2021-02-13 04:54

I saw a video in which Crockford told us not to use the new keyword. He said to use Object.create instead if I\'m not mistaken. Why does he tell us not to use

2条回答
  •  花落未央
    2021-02-13 05:35

    This is a really old question, but…

    When Crockford wrote the article you mention and the discussion linked by Paul Beusterien, there was no Object.create. It was 2008 and Object.create was, at most, a proposal (or really rarely implemented in browsers).

    His final formulation is basically a polyfill:

    if (typeof Object.create !== 'function') {
        Object.create = function (o) {
            function F() {}
            F.prototype = o;
            return new F();
        };
    }
    
    newObject = Object.create(oldObject);
    

    His only use of new is, therefore, to simulate (or emulate) what Object.create must do.

    He doesn’t advise us to use it. He presents a polyfill that uses it, so you don’t have to use it anywhere else.

提交回复
热议问题