findEventFragment

findEventFragment.ts

import {Contract} from "ethers"

export class AmbiguousEvent extends Error {
    constructor(eventName: string, candidates: string[]) {
        super(`Ambiguous event ${eventName}, could be ${candidates.join(' or ')}`);
    }
};

export const findEventFragment = (contract: Contract, eventName: string) => {
    const candidates: [string, object][]
        = Object.entries(contract.interface.events).filter(([key]) => key.startsWith(eventName));
    if (!candidates.length) {
        return undefined;
    } else if (candidates.length === 1) {
        return candidates[0][1];
    } 
    const candidateNames = candidates.map(c => c[0]);
    throw new AmbiguousEvent(eventName, candidateNames);
}