javascript - 为什么不推荐 `with`？有没有更好或其他方法将 "descend"放入对象的 namespace ？

Question

来自MDN :

Using with is not recommended, and is forbidden in ECMAScript 5 strict mode. The recommended alternative is to assign the object whose properties you want to access to a temporary variable.

这似乎是一个很棒/有用/方便的功能。为什么会被人皱眉呢？还有哪些其他方法可以达到这种效果？我不想去:

veryLongNS.y = veryLongNS.myFunc(veryLongNS.x);
veryLongNS.z = 6;
veryLongNS.otherFunc();
veryLongNS.a = {
    a:1,
    b:2,
    c:veryLongNS.processThree(3)
};

Answer 1

这是一个相关的答案: Are there legitimate uses for JavaScript's "with" statement?

另外:http://yuiblog.com/blog/2006/04/11/with-statement-considered-harmful/

以下作为替代方案怎么样？

(function(obj) {
    obj.y = obj.myFunc(obj.x);
    obj.z = 6;
    obj.otherFunc();
    obj.a = {a:1,b:2,c:obj.processThree(3)};
})(myAwkwardlyNamedObjectToBeUsedAsANameSpaceThatIWishToModifyAndNotJustRead);

编辑:为了清楚起见和后代，这也是可能的(并且在大多数情况下比上面的更受欢迎 - 我不会建议在全局范围，但我不建议在全局范围内执行任何操作):

function someFunction() {
    // in some function
    var obj = myAwkwardlyNamedObjectToBeUsedAsANameSpaceThatIWishToModifyAndNotJustRead;
    obj.y = obj.myFunc(obj.x);
    obj.z = 6;
    obj.otherFunc();
    obj.a = {a:1,b:2,c:obj.processThree(3)};
    // ... any other stuff in the function
}