js数组去重set reduce filterset reduce filterset reduce filterset

set

function setqu(arr){
  return [...new Set(arr)]
}

console.log(setqu([1,1,2,2,3,3,4]));

reduce


function reducequ(arr){
  return arr.reduce((old,currect)=>{
     if(!old.includes(currect)) {
      old.push(currect)
     }
     return old
     },[])
}
 
console.log(reducequ([1,1,2,2,3,3,4]));

filter

function filterqu(arr){
  return arr.filter((p,index)=> arr.indexOf(p) === index )
}

console.log(filterqu([1,1,2,2,3,3,4]));