Underscore | findWhere 与 indexBy

let objects = [ 

        { "id": 1,  "name": "可达鸭1", "brandId": 5, "brandName": "小鸡" },

        { "id": 2,  "name": "可达鸭2", "brandId": 5, "brandName": "小鸡" },

        { "id": 3,  "name": "可达鸭3", "brandId": 6, "brandName": "小鸭" },

        { "id": 4,  "name": "可达鸭4", "brandId": 6, "brandName": "小鸭" }

]

_.filter(objects, (v) => { return v.id === 1})

==>[{ "id": 1,  "name": "可达鸭1", "brandId": 5, "brandName": "小鸡" }]

_.findWhere(objects, { id: 1 })

==>{ "id": 1,  "name": "可达鸭1", "brandId": 5, "brandName": "小鸡" }

_.indexBy(objects, 'brandId')

==>{

        5: [{ "id": 1,  "name": "可达鸭1", "brandId": 5, "brandName": "小鸡" },{ "id": 2,  "name": "可达鸭2", "brandId": 5, "brandName": "小鸡" }],

        6: [{ "id": 3,  "name": "可达鸭3", "brandId": 6, "brandName": "小鸭" },{ "id": 4,  "name": "可达鸭4", "brandId": 6, "brandName": "小鸭" }]

}