javascript - 使用 id 号从 JavaScript array.object 获取值

Question

基于下面的var data。如果我只有数字 2，我怎样才能得到 full_name 值？数字 2 对应于 id: 2 并且 full_name 将是 Eric

var data = [{
                id: 0,
                full_name: 'None',
                gravatar_url: 'http://gravatar.com/avatar/31b64e4876d603ce78e04102c67d6144?s=80'
            }, {
                id: 1,
                full_name: 'John',
                gravatar_url: 'http://gravatar.com/avatar/31b64e4876d603ce78e04102c67d6144?s=80'
            }, {
                id: 2,
                full_name: 'Eric',
                gravatar_url: 'http://gravatar.com/avatar/31b64e4876d603ce78e04102c67d6144?s=80'
            }, {
                id: 3,
                full_name: 'Larry',
                gravatar_url: 'http://gravatar.com/avatar/31b64e4876d603ce78e04102c67d6144?s=80'
            }, {
                id: 4,
                full_name: 'Rick',
                gravatar_url: 'http://gravatar.com/avatar/31b64e4876d603ce78e04102c67d6144?s=80'
            }, {
                id: 5,
                full_name: 'John',
                gravatar_url: 'http://gravatar.com/avatar/31b64e4876d603ce78e04102c67d6144?s=80'
            }, {
                id: 6,
                full_name: 'Eric',
                gravatar_url: 'http://gravatar.com/avatar/31b64e4876d603ce78e04102c67d6144?s=80'
            }, {
                id: 7,
                full_name: 'Larry',
                gravatar_url: 'http://gravatar.com/avatar/31b64e4876d603ce78e04102c67d6144?s=80'
            }, {
                id: 8,
                full_name: 'Rick',
                gravatar_url: 'http://gravatar.com/avatar/31b64e4876d603ce78e04102c67d6144?s=80'
            }, {
                id: 9,
                full_name: 'John',
                gravatar_url: 'http://gravatar.com/avatar/31b64e4876d603ce78e04102c67d6144?s=80'
            }, {
                id: 10,
                full_name: 'Eric',
                gravatar_url: 'http://gravatar.com/avatar/31b64e4876d603ce78e04102c67d6144?s=80'
            }, {
                id: 11,
                full_name: 'Larry',
                gravatar_url: 'http://gravatar.com/avatar/31b64e4876d603ce78e04102c67d6144?s=80'
            }, {
                id: 12,
                full_name: 'Rick',
                gravatar_url: 'http://gravatar.com/avatar/31b64e4876d603ce78e04102c67d6144?s=80'
            }];

Answer 1

(data.filter(function(x) { return x.id == 2 })[0] || {}).full_name;
// => "Eric"

data.filter 将只返回符合给定标准的元素；在这种情况下，id 为 2。因为我们只关心一个元素，所以我们只取第一个找到的元素；但如果不存在，.full_name 将给出有关 full_name 未在 undefined 上定义的错误，因此我们放入一个空对象以防万一使用 || 搜索失败{}。