cannot read properties of null
时间: 2023-10-23 20:25:52 浏览: 43
This error occurs when you try to access a property or method of a variable that is null or undefined. In JavaScript, null is a special value that represents the absence of any object value. If you attempt to access a property or method of a null value, you will get a TypeError: Cannot read properties of null error.
To fix this error, you need to make sure that the variable is not null or undefined before accessing its properties or methods. You can use an if statement or the optional chaining operator (?.) to check for null values before accessing a property or method.
For example:
```
let myObj = null;
if (myObj !== null) {
console.log(myObj.property); // This will not be executed because myObj is null
}
console.log(myObj?.property); // This will not throw an error because it uses optional chaining to check for null values
```
In the above example, the if statement checks if myObj is not null before accessing its property. The optional chaining operator also checks for null values before accessing the property, but it does not throw an error if the value is null.
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