1.set
let unique = [...new Set([1,2,3,3,4,5,6,5])]
2.splice
let len = arr.length
for(let i = 0;i < len;i++) {
for(let j = i + 1;j < len;j++) {
if(arr[i] === arr[j]) {
arr.splice(j,1)
j--
len--
}
}
}
console.log(arr)
- j和len都要减一是因为当splice去掉一个元素时，数组的长度会减一，所以j和len都应该减一
3.indexOf
let res = []
for(let i = 0;i < len;i++) {
if(res.indexOf(arr[i]) === -1) res.push(arr[i])
}
console.log(res)
4.includes
for(let i = 0;i < len;i++) {
if(!res.includes(arr[i])) res.push(arr[i])
}
console.log(res)
5.filter
let res = arr.filter((item,index) => {
return arr.indexOf(item) == index
})
console.log(res)
6.map&set
let map = new Map()
let res = []
for(let i = 0;i < arr.length;i++) {
if(!map.has(arr[i])) {
map.set(arr[i],true)
res.push(arr[i])
}
}
console.log(res)
