If a user attempts to destructure the defer object, it can get flagged by @typescript-eslint/unbound-method.

The actual implementation does not at all require a reference to this (resolve+reject is the native value provided in the promise callback), but the typescript definitions do not make it clear, and since it is being pulled off a object, eslint thinks it might need a reference to this.

Example:

async () => {
    const { promise, resolve } = defer(); // eslint fails here

    setTimeout(() => resolve('<abc>'), 100);
    return promise;
};

(This example is an oversimplification, and not a great place to legitimately use this library, but enough to recreate the issue)

The solution is to just update the typing to explicitly declare the this as ignorable (void).