Javascript 如何解决此“未捕获的类型错误：无法将未定义或空值转换为对象”
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How to resolve this " Uncaught TypeError: Cannot convert undefined or null to object "
提问by Pooja Mokariya
My function is :
我的功能是：
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.
我在这条线上遇到错误。
if (typeof Object.keys(value) !== 'nil') {
Need to resolve it. please help to do.
需要解决它。请帮忙做。
回答by Amar Singh
Object.keys(value)returns an arrayand to check if it is undefined or empty do this
Object.keys(value)返回一个数组并检查它是否未定义或为空，请执行此操作
if (typeof Object.keys(value) !== 'undefined' && Object.keys(value).length > 0) {
// You have an array
}
回答by Rock Lee
If you are using React classes that extend PureComponent, then make sure you put your state in the class field, state = {...}, not the State type definition, type State = {...}, or else it will be an error because it actually was null.
如果您使用的是扩展的 React 类PureComponent，那么请确保将您的状态放在类字段中state = {...}，而不是 State 类型定义中，type State = {...}否则它将是一个错误，因为它实际上是 null。
