js数组reduce使用场景案例

数组求和

const arr = [1, 2, 3, 4, 5, 6, 7, 8]
const sum = arr.reduce((a, b) => a + b)

删除重复数据

const array = [1, 2, 3, 'a', 'b', 'c', 1, 2, 3, 'a', 'b', 'c'];
const res = array.reduce((arr, curr) => {
    if (!arr.includes(curr)) arr.push(curr)
    return arr
}, [])

数据项拼接

const arr = [1, 2, 3, 4, 5]
const res = arr.reduce((html, curr) => {
    html += `<li>${curr}</li>`
    return html
}, '')