I am using angular-jwt to to check whether token is expire or not and while using i am getting this error
Type 'string' | null is not assignable to type 'string'
helper = new JwtHelperService();
var token: string = localStorage.getItem('token');
this.helper.isTokenExpired(token); // this line contains the error
Error
First you should check your token
var token: string = localStorage.getItem('token');
if (token) {
this.helper.isTokenExpired(token);
}
Maybe try adding an "if" condition before to check if "token" is not null:
var token: string = localStorage.getItem('token');
if (token)
this.helper.isTokenExpired(token); // this line contains the error
localStorage.getItem('token') returns string|null, so it will cause typescript error if it is cast to stringYour token can't be null. Try
let token = localStorage.getItem('token');
token = token === null ? undefined : token;
this.helper.isTokenExpired(token);
Here is the solution.
let token: any = localStorage.getItem('token');
if (token == null)
token = undefined;
return this.helper.isTokenExpired(token);
You are probably getting this error because your var token can have either string or null value that's why what you should do is provide it a null value as well in option.
like this,
helper = new JwtHelperService();
var token: string|null = localStorage.getItem('token');
this.helper.isTokenExpired(token);
this might help you Thanks
TypeScriptyou are using?nulland it therefore cannot be passed into the argument that does not accept a potential null value. Check if the value is null or not before passing it. Or, if it is null change it’s value to undefined.