使用set对象给数组去重
[...new Set(array)]字符串数组转数字数组
['1', '2', '3'].map(Number); // [1, 2, 3]构造数组
Array(5).fill().map((_,i) => i+1); // [1, 2, 3, 4, 5]数组求和第一弹
function addUp() {
let total = 0;
for(let num of arguments) {
total += num;
}
return total;
}
addUp(1, 2, 3, 4); // 10
- 数组求和第二弹
function addUp() {
const nums = Array.from(arguments);
return nums.reduce((prev, next) => prev + next, 0)
}
addUp(1, 2, 3, 4); // 10
- 类数组转数组
<div class="people">
<p>Jay</p>
<p>Eason</p>
<p>David</p>
</div>
const people = Array.from(document.querySelectAll('.people p'));
const names = people.map(person => person.textContent);
console.log(names); // ['Jay', 'Eason', 'David']
