Typescript淘汰赛保留“此"的最佳方法? [英] Typescript Knockout best way to retain 'this'?

问题描述

这是一个额外的问题 TypeScript和Knockout绑定到"this"问题-lambda函数需要吗? 提出了两种在敲除函数中保留 this 的方法:

This is an extra question to this TypeScript and Knockout binding to 'this' issue - lambda function needed? where two methods of retaining this inside a Knockout function is proposed:

class viewmodelclass {
    declaredinconstructor: (args) => void;
    constructor(public someobjects: Array) {
        this.declaredinconstructor=(args) =>{
        }
    }
    declaredoutside(args) {    
    }
    declaredoutsidecorrectly = (args) => {
        console.log(this);
    };
}

产生此Javascript:

Producing this Javascript:

var viewmodelclass = (function () {
    var _this = this;
    this.declaredoutsidecorrectly = function (args) {
        console.log(_this);
    };
    function viewmodelclass(someobjects) {
        this.someobjects = someobjects;
        this.declaredinconstructor = function (args) {
        };
    }
    viewmodelclass.prototype.declaredoutside = function (args) {
    };
    return viewmodelclass;
})();

如果要在函数内使用 this ，则需要以下HTML代码:

If you want to use this inside the functions, the following HTML code is needed:

<div data-bind="foreach: someobjects" >
   <a href="#" data-bind="click: $parent.declaredinconstructor">link 1</a>
   <a href="#" data-bind="click: $parent.declaredoutside.bind($parent)">link 2</a>
   <a href="#" data-bind="click: $parent.declaredoutsidecorrectly">link 3</a>
</div>

(应该)都可以，但是哪个更正确/更快?

Both (should) work but which is the more correct/faster?

我更喜欢在构造函数中声明它，因为HTML代码更好一些.

I prefer to declare it in the constructor because the HTML code is a bit nicer.

多亏了Basarat的视频，我记得一个关于Typescript的视频-Typescript通过在生成的Javascript中声明_this来帮助您保留它-但仅在必要时！ (如果我没有写console.log(this)_this不会由Typescript生成.)

Thanks to Basarat's video I remembered a video about Typescript - Typescript will help you retain this - by declaring _this in the produced Javascript - but only if necessary! (Had I not written console.log(this) _this would not be produced by Typescript.)

结论-如果正确声明外部实现，则不会泄漏到HTML上，因此，正如阿米塔布(Amitabh)指出的那样，正确的答案是选择最有效的模式:将函数附加到每个实例或原型上./p>

Conclusion - when declared correctly the outside implementation will not leak out to the HTML so the correct answer is, as Amitabh points out, to choose the pattern that is most efficient: Attaching the function to each instance or to the prototype.

推荐答案

绝对喜欢模式1.原因是在模式2中，类的基础实现泄漏到了html中，这在我的书中是很糟糕的.

Definitely prefer pattern 1. The reason is that in pattern 2 the underlying implementation of the classes is leaking into the html which is bad in my book.

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