import { buildMethodCb } from "https://deno.land/x/run_exclusive@v2.2.16/mod.ts";
(Read all before using)
Pending of 'buildMethod' for function that return with callback instead of promise.
The pending of 'build' for creating run exclusive functions that complete via calling a callback function. (Instead of returning a promise).
The only valid reason to use this instead of build()
is to be able to
retrieve the result and/or release the lock synchronously when it's possible.
If you want the callback to be optional it is possible to
define the function as such:
const myRunExclusiveFunction = buildCb((callback?)=> { ... });
Anyway you must call it every time and assume it has been defined:
callback!(...)
.
To see if the user has actually provided a callback you can access the hidden property
callback.hasCallback
.
WARNING: You must also make sure, if you use an optional callback
that the argument before it cannot be a function.
Be aware that the compiler won't warn you against it.
Example: (getLetter:()=> string, callback?:(res:string)=> void)=>{..}
is NOT a valid function to pass to buildMethodCb()
WARNING: the source function should NEVER throw exception!