False positive in @lwc/lwc/valid-graphql-wire-adapter-callback-parameter if a class method signature expects an object with an error property

[amurashincertinia]

There is a bug in @lwc/lwc/valid-graphql-wire-adapter-callback-parameter which falsely reports undecorated class methods if their argument is an object with an error property like in this example:

class C {
    f({ error }) {
        return error;
    }
}

The root cause of the issue is that the graphQlDecorator const is initialised as false if decorators === undefined:

// Check that the @wire decorator is using graphql
const graphQlDecorator =
    decorators !== undefined && // this yields `false`
    decorators.find((decorator) => { // this does not run

Which satisfies the condition for verification:

// Verify that the method definition is using 'errors' not 'error
if (graphQlDecorator !== undefined) { // this evaluates to `true`

Replacing the decorators !== undefined check with an optional chaining operator fixes the issue.

const graphQlDecorator = decorators?.find((decorator) => { // happy days!

An alternative solution without optional chaining:

const graphQlDecorator = (decorators || []).find((decorator) => {