javascript - 在方法链中传递 'this' 上下文(使用应用/调用或绑定(bind))

Question

我试图在这个链接中传递 this 上下文，没有任何“黑客”——我只想使用应用、调用或绑定(bind)(描述如下):

var ArticlesCollection = Backbone.Collection.extend({
    model: ArticleModel,
    parse : function(response) {
        var dateSinceFormatter = this.dateSinceFormatter; // right now solution

        return _.chain(response)
            .map(function(response) {

                if(!_.difference(["id", "title", "link", "source", "image"], _.keys(response)).length) {
                    return {
                        id : (!response.id ? _.uniqueId() : response.id),
                        title : response.title,
                        content : response.preamble,
                        thumbnailUrl : ((!response.image) ? '' : response.image.url),
                        linkUrl: response.link,
                        timeAgo : '',
                        categoryName: '',
                        persistentUrl: response.link,
                        commentsEnabled: false
                    };
                } else {
                    return {
                        id : response.id,
                        title : response.title,
                        content : response.preamble,
                        thumbnailUrl : response.thumbnail.url,
                        linkUrl: response.url,
                        timeAgo : dateSinceFormatter(response.published.datetime, response.published.niceformat), // I want to use this.dateSinceFormatter
                        categoryName: response.mainCategory,
                        persistentUrl: response.persistentUrl,
                        commentsEnabled: response.hasComments
                    };
                }
            })
            .value();
    }
});

有什么想法吗？

Answer 1

在明显的 .bind() 旁边解决方案，Underscore's map (就像 native one )确实为 this context 提供了第三个参数回调:

response.map(function(res) { … }, this)
// or
_.map(response, function(res) { … }, this)