frontend/src/util/setOperation.js

function array_remove_repeat(a) {
  // 去重
  var r = [];
  for (var i = 0; i < a.length; i++) {
    var flag = true;
    var temp = a[i];
    for (var j = 0; j < r.length; j++) {
      if (temp === r[j]) {
        flag = false;
        break;
      }
    }
    if (flag) {
      r.push(temp);
    }
  }
  return r;
}
export default function array_difference(a, b) {
  // 差集 a - b
  //clone = a
  var clone = a.slice(0);
  for (var i = 0; i < b.length; i++) {
    var temp = b[i];
    for (var j = 0; j < clone.length; j++) {
      if (temp === clone[j]) {
        //remove clone[j]
        clone.splice(j, 1);
      }
    }
  }
  return array_remove_repeat(clone);
}