import { SymatemQueryMixin } from "@symatem/query";

...

const backend = await new SymatemQueryMixin(RustWasmBackend);

const {isa} = myRootSymbols;
const { A, baseType } = backend.placeholders(recordingNamespace, {A:undefined, baseType: 'baseType'});

for(const result of backend.query([
    [A, isa, B],
    [B, isa, baseType]
    ]))
    {
        console.log(result.get(A),result.get(B));
    }