NodeJs快速上手3-数组的使用

1、数组的定义

//数组定义let names = ['book','pen','notes']//定义一个空数组let prices = []//push方法增加元素prices.push(300)prices

2、数组作为箭头函数参数 “...”称作为展开运算符

let names = ['book','pen','notes']let prices = []//使用push方法添加元素prices.push(300)prices.push('300')prices.push(20.5)console.log(`Fist product:${names[0]}:${prices[0]}`)//将数组prices的元素转为Number后进行求和运算let sumPrices = (...paras)=>paras.reduce((total,val)=>total + (Number.isNaN(Number(val)?0:Number(val)))​)​let totalPrice = sumPrices(...prices)console.log(`Total price:${totalPrice} ${typeof totalPrice}`)​//运行结果[Running] node "f:\jstest\test2.js"Fist product:book:300Total price:620.5 number​[Done] exited with code=0 in 0.135 seconds

3、数组的合并和迭代

let combineArray = [...names,...prices] //数组合并//数组迭代combineArray.forEach(element=>    console.log(`Combined array element:${element}`)    )  //运行结果[Running] node "f:\jstest\test2.js"Fist product:book:300Total price:620.5 numberCombined array element:bookCombined array element:penCombined array element:notesCombined array element:300Combined array element:300Combined array element:20.5​[Done] exited with code=0 in 0.134 seconds