Can I call a canister function that have a variant as a parameter? How?

Developers
1

I guess this is a silly question but I need to learn somehow jajaj and I can’t find the answer in the forum/sdk docs.

Thanks in advance.

1 Like
2

You can, but to answer the How, it would help to know from where you want to call it (e.g., Motoko, Rust, JavaScript, dfx command line)?

3

Thanks for answering.

I want to call a function (Motoko) from the frontend (React).

Motoko function example:
public shared({ caller }) func addForm ( title : Text, description : Text, fType: FType )

fType:
public type FType = {
#pub;
#priv;
};

Frontend call:
await loggedActor.addForm(“First”, “Testing”, “priv”);

Last parameter can’t be Text obviously, I assume that I have to receive the text in motoko and then use a switch to assign the right parameter but If you have a better way would be awesome.

4

You can pass it in from Javascript as an object with the property name matching the tag and null as its value, eg

await loggedActor.addForm(“First”, “Testing”, { priv: null });

(Aside, tags can also have data attached, in which case you would replace null with the data, eg the Motoko variant

type B = { #this: Text; #that: Nat }

could be passed in from Javascript as

{ this: “hello” }
)

3 Likes
5

Thanks!! Really helpful.