Code for calculating inflation for an account since a given time.

code.js

var StellarSdk = require('stellar-sdk');
var server = new StellarSdk.Server('https://horizon.stellar.org');

// Make sure date is in # of seconds since unix epoch
async function getInflationForAccountSinceDate(account, time) {
    const resp = await server.transactions()
        .forAccount(account)
        .limit(200)
        .order("desc")
        .call();

    const r = resp.records.filter(x => x.source_account === "GDC2XPNEM4YAH22FK2TW7FSVGWQRGZGXLA3DAJLHNJ7YL5L5RSIXXXXX");
    let z = [];
    for (var i = 0; i < r.length; i ++) {
        
        const time_raw = (new Date(r[i].created_at)).getTime();
        if (time_raw > time) {
            const x = await r[i].effects();
            z.push({
                date: r[i].created_at,
                effects: x,
            })
        };
        
    }

    const p = z.map(x => x.effects.records.filter(y => y.type=='account_credited' && y.account == account)[0].amount);

    return p.reduce((sum, x) => sum + parseFloat(x), 0);
}