I'm trying to build an API that fetches the ERC20 tokens in my balance. For this, I'm using nextjs & axios with TypeScript.
The issue I have is that the response outputed by my endpoint returns way too much data, rather than the only 3 props defined in my Token type. Here is how it goes:
util/api.ts
import axios from 'axios';
import console from 'console';
type Token = {
contractAddress: string;
tokenName: string;
tokenSymbol: string;
};
async function getTokens(walletAddress: string) {
const params = {
action: 'tokentx',
address: walletAddress,
offset: 5,
startblock: 0,
endblock: 999999999,
sort: 'asc',
apikey: 'XXXXX'
}
try {
const response = await axios.request<Token[]>({
url: 'https://api.etherscan.io/api?module=account',
params: params
}).then((response) => {
return response.data
});
return response
} catch (error) {
if (axios.isAxiosError(error)) {
console.log('error message: ', error.message);
return error.message;
} else {
console.log('unexpected error: ', error);
return 'An unexpected error occurred';
}
}
}
export async function getWalletBalance(walletAddress: string) {
let tokens = await getTokens(walletAddress)
return tokens
}
pages/api/balances/[network]/[wallet.ts]
import { NextApiRequest, NextApiResponse } from "next";
import NextCors from "nextjs-cors";
import { getWalletBalance } from "../../../../util/api";
export default async (req: NextApiRequest, res: NextApiResponse) => {
await NextCors(req, res, {
methods: ["GET"],
origin: "*",
optionsSuccessStatus: 200,
});
const { wallet } = req.query as { wallet: string };
try {
const balance = await getWalletBalance(wallet);
res.json({ balance });
} catch (e) {
res.status(400).json({ error: (e as Error).message });
}
};
How can I make it so that getTokens() only returns an array of Token with only the contractAddress, tokenName, tokenSymbol props, in order for the endpoint to output only the JSON I need?
If you're looking to reduce the data returned from the api.etherscan.io
in your own proxy api you'd need to filter out only the props you need. you can achieve it like so:
.then((response) => {
return response.data.map(x=>({
contractAddress:x.contractAddress
tokenName:x.tokenName
tokenSymbol:x.tokenSymbol
});
})
I don't know much about the 3rd party endpoint but I assuming its a REST endpoint so you couldn't take advantage of Graphql's ability to reduce overfetching by specifying the properties of the type you're interested in.