trust.js

const RippleAPI = require('ripple-lib').RippleAPI;

const api = new RippleAPI({
    server: 'wss://testnet.xrpl-labs.com' // Public rippled server
});
api.connect().then(() => {
    /* begin custom code ------------------------------------ */
    const wallet_hot = 'r4fCw4QyjNdXQF1rYUo71EbZ13Gq8TwNuS';

    a_acc = {
        address: 'rsUgwE4czke7cRHUJuJEK56ZsoZyRvTDBn',
        secret: 'ssdNpZMTyRiydk1czPtsGvq7Dc13w'
    }

    b1_acc = {
        address: 'rB9SSWDvwCPvE9Q2axSH7YWVYLMbEzpPd2',
        secret: 'shu5WFbh3siTu25KKpvynauzLjntE'
    }

    b2_acc = {
        address: 'rDfug7fMs3CxXzZ1eTsxxSRynYjkJjYSip',
        secret: 'snC8TxEJPTqEa2n1LG7BwUMHwY8AT'
    }

    tx = {
        TransactionType: "TrustSet",
        Account: wallet_hot,
        LimitAmount: {
            currency: "786E617375733838313630723130313430303031",
            issuer: "rarRYh3WZCkSKWWpJiq1kxfZwBuZLMgazm",
            value: "10000000"
        },
        Flags: "0x00020000",
        Fee: "60"
    }
    api.prepareTransaction(tx).then(prepared => {
        console.log(prepared);
        a_sign = api.sign(prepared.txJSON, a_acc.secret, {'signAs': a_acc.address}).signedTransaction;
        b1_sign = api.sign(prepared.txJSON, b1_acc.secret, {'signAs': b1_acc.address}).signedTransaction;
        b2_sign = api.sign(prepared.txJSON, b2_acc.secret, {'signAs': b2_acc.address}).signedTransaction;

        console.log(a_sign);
        console.log(b1_sign);
        console.log(b2_sign);
        let combinedTx = api.combine([a_sign, b1_sign, b2_sign]);
        console.log(combinedTx)
        // NOTE: On this step it may brake so I used to copy blob and submit using https://test.bithomp.com/submit/
        api.submit(combinedTx.signedTransaction).then(response => {
            console.log("should be ok now");
            console.log(response.tx_json.hash);
            return api.disconnect();
        }).catch(console.error);
    });

    return api.getAccountInfo(wallet_hot);

}).then(info => {
    console.log(info);
    console.log('getAccountInfo done');

    /* end custom code -------------------------------------- */
}).then(() => {
    return api.disconnect();
}).then(() => {
    console.log('done and disconnected.');
}).catch(console.error);