第一章JS复习

//js forEach every same reduce不产生新数组 function square(num){ console.log(num,num*num); } let nums=[1,2,3,4,5,6,7,8,9]; nums.forEach(square); console.log('nums:',nums); function isEven(num){ return num %2==0; } let nums=[2,4,6,8,9]; // let even=nums.every(isEven); let even=nums.some(isEven); if (even) { console.log("all numbers are even"); }else{ console.log("not all numbers are even"); } function add(runningTotal,currentValue){ return runningTotal+currentValue; } let nums=[1,2,3,4,5,6,7,8,9,10]; let sum=nums.reduce(add); console.log("add:",sum); function concat(accumulatedString,item){ return accumulatedString+item; } let words=['the ','quick ','brown ','fox ']; let sentence=words.reduce(concat,'haung '); console.log(sentence);