reduce的特殊用法

//计算数组中每个元素出现的次数var arr = ["apple","orange","apple","orange","pear","orange"];

function getWordCnt(){return arr.reduce(function(prev,next){prev[next] = (prev[next] 1) || 1;//其中的'='相当于'：',给对象赋值return prev;},{});}

console.log(getWordCnt());

 

//数组去重let arr1 = [10,1,13,5,6,19,10,13];let result = arr1.sort(compare).reduce((init, current)=>{ if(init.length===0 || init[init.length-1]!==current){//判断是否为第一个数值，或上个数值是否不等于当前数值 init.push(current); } return init;}, []);function compare(a,b){ return a-b;}console.log(result); //[1, 5, 6, 10, 13, 19]

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