原生用法
直接使用的API
_.reject
根據條件去除某個元素。
var foo = [ {id: 0, name: "aaa", age: 33}, {id: 1, name: "bbb", age: 25} ] var bar = _.reject(foo, ['id', 0]) //bar = [{id: 1, name: "bbb", age: 25}]_.pick
根據第二個參數的key的數組，篩選第一個參數中的值並返回
var foo = {id: 0, name: "aaa", age: 33} var bar = _.pick(foo, ['name', 'age']) //bar = {name: "aaa", age: 33}_.keys
返回object中的所有key
var foo = {id: 0, name: "aaa", age: 33} var bar = _.keys(foo) //bar = ['id', 'name', 'age']_.cloneDeep
深度拷貝，這個不用多說了吧，js中基礎類型以外的類型，都會默認拷貝備份var bar = _.cloneDeep(foo)
_.find
查找數組
var foo = [ {id: 0, name: "aaa", age: 33}, {id: 1, name: "bbb", age: 25} ] var bar = _.find(foo, ['id', 0]) //bar = {id: 0, name: "aaa", age: 33}注意一下如果沒找到的話，會返回undefined，要處理一下
_.keyBy
以某個屬性為鍵，將數組轉為對象
var foo = var foo = [ {id: 0, name: "aaa", age: 33}, {id: 1, name: "bbb", age: 25} ] var bar = _.keyBy(foo, 'name') //bar = { // aaa: {id: 0, name: "aaa", age: 33}, // bbb: {id: 1, name: "bbb", age: 25} //}_.filter
根據條件過濾出符合條件的元素，返回新數組
var foo = var foo = [ {id: 0, name: "aaa", age: 33}, {id: 1, name: "bbb", age: 25} ] var bar = _.filter(foo, ['name', "aaa"]) //bar = { // aaa: {id: 0, name: "aaa", age: 33} //}_.map
從集合中挑出一個key，將其值作為數組返回
var foo = var foo = [ {id: 0, name: "aaa", age: 33}, {id: 1, name: "bbb", age: 25} ] var bar = _.map(foo, 'name') //bar = ["aaa", "bbb"]_.max/_.min/_.sum
數組中最大值、最小值、數組求和
var foo = [1, 2, 3, 4] var bar = _.max(foo) //bar = 4 bar = _.min(foo) //bar = 1 bar = _.sum(foo) //bar = 10_.pad/_.padStart/_.padEnd
在兩端、開頭、末尾補齊字符
var foo = "helloworld" var bar = _.pad(foo, 14, '-') //bar = --helloworld-- bar = _.padStart(foo, 14, '-') //bar = ----helloworld bar = _.padEnd(foo, 14, '-') //bar = helloworld----組合用法
如果說上面是基礎技能，那么下面奉上幾個炫酷的組合技：
選出json數組中id最大的一項
var foo = [ {id: 0, name: "aaa", age: 33}, {id: 1, name: "bbb", age: 25} ] var bar = _.find(foo, ['id', _.max(_.map(foo, 'id'))]) // bar = {id: 1, name: "bbb", age: 25}ps:也可以用maxBy某個key來代替
更新json數組中某一項的值
var foo = [ {id: 0, name: "aaa", age: 33}, {id: 1, name: "bbb", age: 25} ] let list = _.keyBy(foo, 'id') list[0].name = "ccc" var bar = _.map(list) // bar = [ // {id: 0, name: "ccc", age: 33}, // {id: 1, name: "bbb", age: 25} //]