数组去重:

// 方法一
function arrUnique(arr, key) {
  var arrUni = []
  if(key) {
    const obj = {}
    arrUni = arr.reduce((accumulator, currentValue) => {
      obj[currentValue[key]] ? '' : currentValue[key] == true && accumulator.push(currentValue)
    }, [])
  }
  arrUni = arr.reduce((accumulator, curretValue) => {
    !accumulator.includes(currentValue) && accumulator.push(currentValue)
  }, [])
  return arrUni
}

// 方法二function arrUnique2(arr) {
  var result = [], hash = {}
  for(var i = 0, elem; (elem = arr[i]) != null; i++) {
    if(!hash[elem]) {
      result.push(elem)
      hash[elem] =true
    }
  }
  return result
}
arrUnique2(['red','blue','green','pink','yellow','blue','black','red'])