Get the Promise of Web3 accounts

getAccountsPromise.js

web3.eth.getAccountsPromise = function () {
    return new Promise(function (resolve, reject) {
        web3.eth.getAccounts(function (e, accounts) {
            if (e != null) {
                reject(e);
            } else {
                resolve(accounts);
            }
        });
    });
};