Vue.js方法 - 在lodash _each循环中访问`this`

Question

我的应用有一个collaborators列表，每个旁边都有一个复选框。

用户可以检查多个协作者，然后单击按钮将其删除，从而触发以下Vue.js方法：

methods: {
        remove: function () {
            if (confirm('Are you sure you want to delete these collaborators?')) {
                axios.get('/collaborators/api/destroy', {
                    params: {
                        ids: this.selectedCollaborators
                    }
                })
                    .then(response => {

                        // Loop through the `selectedCollaborators` that were deleted and
                        // remove them from `collaborators`
                        _.each(this.selectedCollaborators, function (value, key) {

                            console.log('Remove collaborator: ' + value);

                            // Following line produces: TypeError: Cannot read property 'collaborators' of undefined
                            this.collaborators.splice(this.collaborators.indexOf(value), 1)

                        });
                    });

            }
        },
// [...etc...]

正如你可以在上面的代码中看到，处理Ajax响应的时候，我试图遍历每个的selectedCollaborators使用lodash的_each ，并为每一个，从移除合作者collaborators利用拼接的数据属性。

问题是this.collaborators在_.each函数中不可访问，并产生以下错误：

TypeError: Cannot read property 'collaborators' of undefined

我该如何解决这个/有更好的方法来解决这个问题吗？

Answer 1

你可以做的是将this保存在一个变量中。

methods: {
        remove: function () {
            if (confirm('Are you sure you want to delete these collaborators?')) {
                axios.get('/collaborators/api/destroy', {
                    params: {
                        ids: this.selectedCollaborators
                    }
                })
                    .then(response => {
                        const t = this;
                        // Loop through the `selectedCollaborators` that were deleted and
                        // remove them from `collaborators`
                        _.each(this.selectedCollaborators, function (value, key) {
                            console.log('Remove collaborator: ' + value);
                            t.collaborators.splice(t.collaborators.indexOf(value), 1)
                        });
                    });

            }
        },
// [...etc...]

Answer 2

尝试用词汇上下文替换函数到箭头函数：

methods: {
    remove: () => {
        if (confirm('Are you sure you want to delete these collaborators?')) {
            axios.get('/collaborators/api/destroy', {
                params: {
                    ids: this.selectedCollaborators
                }
            })
                .then(response => {

                    // Loop through the `selectedCollaborators` that were deleted and
                    // remove them from `collaborators`
                    _.each(this.selectedCollaborators, (value, key) => {

                        console.log('Remove collaborator: ' + value);

                        // Following line produces: TypeError: Cannot read property 'collaborators' of undefined
                        this.collaborators.splice(this.collaborators.indexOf(value), 1)

                    });
                });

        }
    },