Snapshotting Opensea collections

snapShop.js

async function snapShot(slug, address, totalTokens) {
    const API_KEY = ""

    // Step 1 - Pagination
    const pages = Math.ceil(totalTokens / 50); // Paginate to account for OpenSea api call limits.
    let offSet = 0;

    let num = 0;
    let totalOwned = 0;
    let foundTokens = 0;
    let holderAddresses = {};

    for (let i = 0; i < pages; i++) {
        offSet = i * 50;

        console.log('page:', i);
        const response = await fetch(`https://api.opensea.io/api/v1/assets?order_direction=desc&offset=${offSet}&limit=50&collection=${slug}`);
        const listOfTokens = await response.json();

        // Loop through found tokens
        for (const asset of listOfTokens.assets) {
            foundTokens++;

            // Step 2 - Smashing my head on the desk
            const url = `https://deep-index.moralis.io/api/nft/contract/${address}/token/${asset.token_id}/owners?chain=eth&chain_name=mainnet&format=decimal&order=name.DESC`;
            const header = {
                method: 'GET', headers: {
                    'X-API-Key': API_KEY
                }
            }
            const fetchResult = await fetch(url, header);
            const jsonResult = await fetchResult.json();
            totalOwned += jsonResult.total;

            // Step 3 - Filtering holders
            // iterate through results
            for (const result of jsonResult.result) {
                if (!holderAddresses[result.owner_of]) {
                    holderAddresses[result.owner_of] = 1;
                } else {
                    holderAddresses[result.owner_of]++;
                }
            }
            num++;
        }
    }

    // Step 4 - Saving and checking
    // Log useful data
    console.log('total tokens:', foundTokens);
    console.log('total owned:', totalOwned);
    console.log('total holders', Object.keys(holderAddresses).length);

    // Write holders to json file
    fs.writeFile(`./src/snapshots/${slug}-holders.json`, JSON.stringify(holderAddresses), {flag: 'w'}, function(err) {
        // Log error if fail saving fails.
        if (err) return console.log(err);
    });
}