Using the fetch() function of Workers service binding as a const

[nicougou]

Hi !
Did anyone ever manage to achieve something similar to this, using service binding in node ?

const fetchFn = env.MY_SERIVE_BIND?.fetch ?? fetch;
await fetch('url', {})

I am always getting [ERROR] TypeError: Illegal invocation.

I would have thought this could be possible, the goal is to be able to pass the fetch() function to other clients.

I tried using env.MY_SERIVE_BIND?.fetch.bind(globalThis) but it didn't help.

[kentonv]

To turn a method into a stand-alone function, you need to bind the method to the object you got it from, not to globalThis:

env.MY_SERVICE_BIND.fetch.bind(env.MY_SERVICE_BIND)

Note that this is generally true of all methods in JavaScript, not specific to fetch or to service bindings.

[nicougou]

@kentonv that was incredibly helpful, thanks !

While this was an obvious lack of knowledge on my end, this could be very helpful in the official docs, replacing the fetch client in some sdk that allows it by a service binding can help a lot :)