javascript - JavaScript 中的动态实例化

Question

除了 eval(`o = new ${className}(${args.join(", ")})`) 之外，还有其他方法可以使用可变参数实例化对象吗名单？

例如:var foo = instantiate(className, [arg1, arg2, ...])

Answer 1

您可以像这样用可变参数列表实例化一个对象:

function instantiate(className, args) {
    var o, f, c;
    c = window[className]; // get reference to class constructor function
    f = function(){}; // dummy function
    f.prototype = c.prototype; // reference same prototype
    o = new f(); // instantiate dummy function to copy prototype properties
    c.apply(o, args); // call class constructor, supplying new object as context
    o.constructor = c; // assign correct constructor (not f)
    return o;
}

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旁注:您可能希望传递对类构造函数的直接引用:

var foo = instantiate(Array, [arg1, arg2, ...]);
// Instead of:
var foo = instantiate("Array", [arg1, arg2, ...]);

... 这使得它与非全局函数兼容。