你想要得到一個(gè)與你的某些屬性匹配的數(shù)組對(duì)象。
你有一系列的對(duì)象，如：
cats = [
{
name: "Bubbles"
favoriteFood: "mice"
age: 1
},
{
name: "Sparkle"
favoriteFood: "tuna"
},
{
name: "flyingCat"
favoriteFood: "mice"
age: 1
}
]你想用某些特征來(lái)濾出想要的對(duì)象。例如：貓的位置 ({ 年齡: 1 }) 或者貓的位置 ({ 年齡: 1 , 最?lèi)?ài)的食物: "老鼠" })
你可以像這樣來(lái)擴(kuò)展數(shù)組：
Array::where = (query) ->
return [] if typeof query isnt "object"
hit = Object.keys(query).length
@filter (item) ->
match = 0
for key, val of query
match += 1 if item[key] is val
if match is hit then true else false
cats.where age:1
# => [ { name: 'Bubbles', favoriteFood: 'mice', age: 1 },{ name: 'flyingCat', favoriteFood: 'mice', age: 1 } ]
cats.where age:1, name: "Bubbles"
# => [ { name: 'Bubbles', favoriteFood: 'mice', age: 1 } ]
cats.where age:1, favoriteFood:"tuna"
# => []這是一個(gè)確定的匹配。我們能夠讓匹配函數(shù)更加靈活：
Array::where = (query, matcher = (a,b) -> a is b) ->
return [] if typeof query isnt "object"
hit = Object.keys(query).length
@filter (item) ->
match = 0
for key, val of query
match += 1 if matcher(item[key], val)
if match is hit then true else false
cats.where name:"bubbles"
# => []
# it's case sensitive
cats.where name:"bubbles", (a, b) -> "#{ a }".toLowerCase() is "#{ b }".toLowerCase()
# => [ { name: 'Bubbles', favoriteFood: 'mice', age: 1 } ]
# now it's case insensitive處理收集的一種方式可以被叫做 “find” ，但是像 underscore 或者 lodash 這些庫(kù)把它叫做 “where” 。
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