我有一个如下所示的模型
this.Model
Model {class: undefined items: Array(0) tag: undefined launch: undefined length: undefined name: undefined Id: "de4d704a-b754-4546-b3ab-f0c131eba84a" time: "15:36" tonnage: undefined}
模型中唯一始终具有值的对象是 Id 和时间。
我有一个 if 语句,它遍历我的每个对象以检查其是否为 null,如下所示:
if ( this.Model.class == null && this.Model.name == null && this.Model.tag== null && this.Model.launch == null && this.Model.length == null && this.Model.tonnage == null && this.Model.items.length == 0)
{
//does something in here
}
所以我想检查除时间和 ID 之外的所有对象是否为空,是否有比我在 if 语句中使用上述方法更好的方法?
答案 0 :(得分:2)
我将创建一个函数来使用 Object.entries
和 Array.every
进行检查。
此解决方案的好处:
Javascript 中的代码段。
function checkAllKeysExceptGivenKeysToBeNullable(obj, keys) {
return Object.entries(obj).every(([
key,
value,
]) => {
// If the key has to be ignored
if (keys.includes(key)) {
return true;
}
// Check the value to be nullable
return value === null ||
value === void 0 ||
(value instanceof Array && value.length === 0);
});
}
console.log(checkAllKeysExceptGivenKeysToBeNullable({
class: undefined,
items: Array(0),
tag: undefined,
launch: undefined,
length: undefined,
name: undefined,
Id: 'de4d704a-b754-4546-b3ab-f0c131eba84a',
time: '15:36',
tonnage: undefined,
}, [
'Id',
'time',
]));
console.log(checkAllKeysExceptGivenKeysToBeNullable({
class: undefined,
items: Array(0),
tag: 'nope',
launch: undefined,
length: undefined,
name: undefined,
Id: 'de4d704a-b754-4546-b3ab-f0c131eba84a',
time: '15:36',
tonnage: undefined,
}, [
'Id',
'time',
]));
function checkAllKeysExceptGivenKeysToBeNullable<T extends {
[key in keyof T]: null | undefined | Array<unknown> | unknown;
}>(obj: T, keys: (keyof T)[]): boolean {
return Object.entries(obj).every(([
key,
value,
]) => {
if (keys.includes(key as keyof T)) {
return true;
}
return value === null ||
value === void 0 ||
(value instanceof Array && value.length === 0);
});
}
console.log(checkAllKeysExceptGivenKeysToBeNullable({
class: undefined,
items: Array(0),
tag: undefined,
launch: undefined,
length: undefined,
name: undefined,
Id: 'de4d704a-b754-4546-b3ab-f0c131eba84a',
time: '15:36',
tonnage: undefined,
}, [
'Id',
'time',
]));
console.log(checkAllKeysExceptGivenKeysToBeNullable({
class: undefined,
items: Array(0),
tag: 'nope',
launch: undefined,
length: undefined,
name: undefined,
Id: 'de4d704a-b754-4546-b3ab-f0c131eba84a',
time: '15:36',
tonnage: undefined,
}, [
'Id',
'time',
]));
答案 1 :(得分:1)
玩了一会之后,我想出了一个使用 Object.keys()
/**
* Checks if all of the objects values are null, except for keys in param except
* @param obj: The object to test
* @param except (optional): keys to omit the null check on
*/
function checkIfPropertiesNull(obj: {[key: string]: unknown}, except: string[] = []): boolean {
const keys = Object.keys(obj).filter(key => !except.includes(key));
for(const key of keys){
if(obj[key] !== null){
return false;
}
}
return true;
}
console.log(checkIfPropertiesNull({ id: 1, name: 'mike', city: null }, ['id', 'name'])); // true, because id and name are not checked
console.log(checkIfPropertiesNull({ id: 1, name: 'mike', city: 'Munich' }, ['id', 'name'])); // false, city isn't null
答案 2 :(得分:0)
嗯,在这种情况下你有两个选择:
function checkProperties(obj) {
for (var key in obj) {
if (obj[key] !== null && obj[key] != "")
return false;
}
return true;
}
var obj = {
x: null,
y: "",
z: 1
}
checkProperties(obj) //returns false
let report = {
property1: null,
property2: null,
}
let result = !Object.values(report).every(o => o === null);
console.log(result);
答案 3 :(得分:0)
for (let prop in Modal) {
if (Modal.prop != time && Modal.prop != id && Modal[prop] != null) {
return false
}
}
return true
如果除 ID 和时间之外的所有属性都为空,则返回 true。