Underscore.JS where方法

Underscore.JS where方法

语法

_.where(list, properties)

where方法在给定的元素列表上进行迭代，对每个元素调用谓词。它返回属性中所有匹配的键值对。

在列表中查找每个值，返回与属性中列出的键值对匹配的所有值的数组。

示例

var _ = require('underscore');

var list = [{"title": "Learn Java", "Author": "Sam", "Cost": 100},
   {"title": "Learn Scala", "Author": "Joe", "Cost": 200},
   {"title": "Learn C", "Author": "Sam", "Cost": 200} ]

//Example 1. find books whose author is Sam
var result = _.where(list, { "Author": "Sam" });
console.log(result);

//Example 2. find books whose cost is 200
var result = _.where(list, { "Cost": 200 });
console.log(result);

将上述程序保存在 tester.js 中。运行以下命令来执行该程序。

命令

>node tester.js

输出

[
  { title: 'Learn Java', Author: 'Sam', Cost: 100 },
  { title: 'Learn C', Author: 'Sam', Cost: 200 }
]
[
  { title: 'Learn Scala', Author: 'Joe', Cost: 200 },
  { title: 'Learn C', Author: 'Sam', Cost: 200 }
]