How to assign string | undefined to string in TypeScript?
The typescript compiler performs strict null checks, which means you can't pass a string | undefined variable into a method that expects a string.
To fix this you have to perform an explicit check for undefined before calling luminaireReplaceLuminaire().
In your example:
private selectedSerialForReplace(): string | undefined { return this.selectedSerials.pop();}luminaireReplaceLuminaire(params: { "serial": string; "newserial": string; }, options?: any): FetchArgs { ............}const serial = this.selectedSerialForReplace();if(serial !== undefined) { luminaireReplaceLuminaire({serial, newserial: response.output});}
If you are sure that serial could not be undefined you can use the ! post-fix operator
luminaireReplaceLuminaire({serial: this.selectedSerialForReplace()!, newserial: response.output});