1.
let arr = [1,2,1,2,3,5,4,5,3,4,4,4,4];
let result = arr.sort().reduce((init, current)=>{
if(init.length===0 || init[init.length-1]!==current){
init.push(current);
}
return init;
}, []);
console.log(result); //[1,2,3,4,5]
2. Array.prototype.distinct = function() {
var arr = this,
result = [],
i,
j,
len = arr.length;
for (i = 0; i < len; i++) {
for (j = i + 1; j < len; j++) {
if (arr[i] === arr[j]) {
j = ++i;
}
}
result.push(arr[i]);
}
return result;
}
3.使用set集合给元素去重复,返回的就不是数组了。。