[SalesForce] Lightning Web Component Use Cases

In the salesforce lightning design system docs here

Unlike LC (Aura), the parameters sent back are different. If you reach the ".then", the call was successful, otherwise there was an error. There's no need for you to check if the result was successful.

submitResponse(){
    this.showSpinner = true;
    updateRecords({recordId: this.recordId, newStatus: this.newStatus})
    .then(() => {
        this.showToast("Success!", "Success", "No error!");
        this.showSpinner = false;
    })
    .catch(error => {
        this.showToast("Error!", "error", "error");
        this.error = error;
        this.showSpinner = false;
    });
}