@syncswap/sdk/dist/esm/tokens/fetchToken.js

SyncSwap TypeScript SDK for building DeFi applications

import { Token } from "./token.js";
import ContractRegistry from "../contracts/contractRegistry.js";
import { TokenRegistry } from "./tokenRegistry.js";
// Token metadata are relatively immutable so it's safe to keep a static cache.
const cacheMap = new Map();
export default async function fetchToken(provider, address) {
    address = address.toLowerCase(); // fix case
    if (address === Token.ETHER.address) {
        return Token.ETHER;
    }
    const known = TokenRegistry.getTokenByAddress(address);
    if (known) {
        return known;
    }
    const cached = cacheMap.get(address);
    if (cached) {
        return cached;
    }
    try {
        const tokenHelper = ContractRegistry.getContractByName("token_helper");
        const { decimals, symbol, name, isPermit } = await retry(async () => await tokenHelper.tokenMetadata(address));
        //console.log('fetchToken', decimals, symbol, name, address);
        // invalid tokens (contract that is not a token?)
        if (decimals === 0 && symbol == "" && name == "") {
            return null;
        }
        const token = new Token(address, decimals, symbol == "" ? address.substring(0, 6) : symbol, name == "" ? address.substring(0, 8) : name, isPermit);
        cacheMap.set(address, token);
        return token;
    }
    catch (error) {
        console.error("fetchToken: error on fetch token", address, error);
        return null;
    }
}
async function retry(doFunc, retry = 5) {
    return new Promise(async (resolve, reject) => {
        for (let i = 0; i < retry; i++) {
            try {
                // use promise.race to kill first promise when execute over 10 seconds
                const res = await Promise.any([
                    doFunc(),
                    new Promise((resolve) => {
                        setTimeout(() => resolve(false), 10000);
                    }),
                ]);
                if (res === false) {
                    throw new Error("RPC Error: JsonRpcEngine: Response timeout");
                }
                return resolve(res);
            }
            catch (error) {
                if (i === retry - 1) {
                    console.error("retry: request failed after retry", doFunc, error);
                    return reject(error);
                }
                else {
                    await sleep(100);
                }
            }
        }
    });
}
async function sleep(timeout) {
    await setTimeout(() => {
        // do nothing
    }, timeout);
}
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