如何解决这个“Uncaught TypeError：无法将undefined或null转换为object”

Question

My function is :

function collect_que_ids(e) {
  var val = e.val();
  var data_lo = e.attr('data-lo');
  new_hash = {};
  new_hash[val] = data_lo;
  if(e.is(':checked')){
    if(checked_box_hash.includes(new_hash)){
      checked_box_hash;
    }else{
      checked_box_hash.push(new_hash);
    }
  }
  else{
    new_hash_key = Object.keys(new_hash)[0]
    new_hash_value = new_hash[new_hash_key]
    $.each(checked_box_hash, function(key, value){
      if (typeof Object.keys(value) !== 'nil') {
        current_key = Object.keys(value)
        if (current_key[0] == new_hash_key && value[current_key[0]] == new_hash_value) {
          checked_box_hash.splice(key, 1)
        }
      }
    })
  }
};

I am getting error on this line.

if (typeof Object.keys(value) !== 'nil') {

Need to resolve it. please help to do.

Answer 1

Object.keys(value) returns an array and to check if it is undefined or empty do this

 if (typeof Object.keys(value) !== 'undefined' && Object.keys(value).length > 0) {
        // You have an array 
    }

Answer 2

如果您正在使用扩展PureComponent React类，那么请确保将您的状态放在类字段state = {...} ，而不是State类型定义中， type State = {...} ，否则它将是错误，因为它实际上是null。