Get the Promise of an Ethereum transaction receipt when it is finally mined

getTransactionReceiptMined.js

const Promise = require("bluebird");
const sequentialPromise = require("./sequentialPromise.js");

/**
 * @param {!string | !Array.<!string>} txHash, a transaction hash or an array of transaction hashes.
 * @param {Number} interval, in seconds.
 * @returns {!Promise.<!object> | !Promise.<!Array.<!object>>} the receipt or an array of receipts.
 */
module.exports = function getTransactionReceiptMined(txHash, interval) {
    const self = this;
    const transactionReceiptRetry = () => self.getTransactionReceipt(txHash)
        .then(receipt => receipt != null
            ? receipt
            : Promise.delay(interval ? interval : 500).then(transactionReceiptRetry));
    if (Array.isArray(txHash)) {
        return sequentialPromise(txHash.map(
            oneTxHash => () => self.getTransactionReceiptMined(oneTxHash, interval)));
    } else if (typeof txHash === "string") {
        return transactionReceiptRetry();
    } else {
        throw new Error("Invalid Type: " + txHash);
    }
};

If I do:

await web3.eth.getTransaction( txn_id );

It will wait till it is mined - correct?

@prographo, No, it will not wait till it is mined. If it is not mined yet, some of the fields (such as 'blockNumber') of the resolved transaction object would be null. See the document here: https://web3js.readthedocs.io/en/1.0/web3-eth.html#gettransaction