Getting function signatures from a Contract's interface without giving parameters.

[GFJHogue]

Hello!

So I'm interested in grabbing a function's signature (or the 4 byte hash of it).

This works fine:

someContract.interface.functions.someFunction().signature;

// or the hash
someContract.interface.functions.someFunction().data.substring(0,10);

but if someFunction() has parameters, interface.js requires me to provide them despite them not being needed for the signature.

One way to work around this is to pass dummy, yet valid, values to the function:

// someFunction(uint, uint[5])

someContract.interface.functions.someFunction(0, new Array(5)) //...

but this sort of hardcoding pretty much defeats the point of grabbing the signature.

I just want to see if there is a way of doing this, and if not, if this would be something you would consider adding to ethers.

[GFJHogue]

I took a crack at how I would handle this: e31bdc4

This way we only throw when 0 < # of params < # required and omit result.data when there are required params and none are provided.

[ricmoo]

This is a good idea, since it is known without requiring parameters. I will add it to the properties attached to the function.

So, you will be able to use: someContract.interface.functions.someFunction.signature.

[ricmoo]

Added in fb65772.

It has been published to npm and will get pushed to the CDN tomorrow.

Thanks! Great idea.

[wellitongervickas]

Get first the fragment of abi function

const fragment = contract.interface.getFunction(method)

Then, get bytes4 signature of function

const selectorHash = contract.interface.getSighash(fragment)