Question

我有一个关于通过引用传递的问题。特别是我将wf传递给wordFormUpdateSubmit。

当我这样做时：wf = response.data;它不会改变word.wordForms中的任何内容
当我这样做时：self.word.wordForms[key] = response.data;它正确地更改了word.wordForms中的wf内容

我的问题是为什么不通过引用传递，为什么wf = response.data;不起作用？

 wordFormCheckAndUpdate = (): ng.IPromise<any> => {
    var self = this;
    var promises = [];
    angular.forEach(self.word.wordForms, function (wf, key) {
        var updatePromise = self.wordFormUpdateSubmit(wf, key);
        promises.push(updatePromise);         
    });
    return self.$q.all(promises);
 };

  wordFormUpdateSubmit = (wf: IWordForm, key: number): ng.IPromise<any> => {
    var self = this;
    return self.$http({
        url: self.ac.dataServer + "/api/WordForm/Put",
        method: "PUT",
        data: wf
    })
        .then(
        (any => {
            // This does not correctly populate self.word.wordForms[0]
            wf = response.data;

            // This works
            self.word.wordForms[key] = response.data;


        });
   }

Answer 1

JavaScript没有传递引用，它有“call by sharing”。

如果为函数参数指定新值，则不会对传递给函数的原始值进行任何更改。它只会覆盖参数。

这应该是您尝试做的可行（和更清洁）的替代方案：

wordFormCheckAndUpdate = (): ng.IPromise<any> => {
    var self = this;

    return self.$q.all(self.word.wordForms.map((wf, key) =>
        self.wordFormUpdateSubmit(wf, key)
    ))
    .then(function (values) {
        self.word.wordForms = values;
    });
};

wordFormUpdateSubmit = (wf: IWordForm, key: number): ng.IPromise<any> => {
    var self = this;
    return self.$http({
        url: self.ac.dataServer + "/api/WordForm/Put",
        method: "PUT",
        data: wf
    })
    .then(response => response.data);
}

当我从.forEach传递时，为什么我会丢失对象引用？

1 个答案: