Checking Payment Paths with path_find | XRPL Development in JavaScript - Level 3

This guide explains cross-currency payments by dealing with A.USD issued by Issuer A and B.EUR issued by Issuer B.

In the previous section, Alice provided liquidity by placing an offer to sell A.USD issued by Issuer A and buy B.EUR issued by Issuer B.

In this section, before executing a cross-currency payment, we will introduce the path_find command to search for payment paths.

Prerequisites

Alice has already provided liquidity by placing an offer to sell A.USD issued by Issuer A and buy B.EUR issued by Issuer B.

Daniel needs to make a payment to Charlie, who wants to receive A.USD. However, Daniel currently does not hold any A.USD.

Daniel only holds XRP or B.EUR issued by Issuer B and is considering whether he can exchange his B.EUR. If someone is willing to exchange B.EUR for the desired amount of A.USD, Daniel should be able to send his B.EUR as A.USD to Charlie.

Daniel wants to search if it is possible to send his B.EUR to Charlie as A.USD.

Creating the Script

1. Create a new file named pathFinding.js in your project directory.

2. Paste the following code into pathFinding.js.

   import { Client, xrpToDrops } from 'xrpl';
   import { wallets } from './wallets.js';
   
   const client = new Client('wss://s.altnet.rippletest.net:51233');
   
   const main = async () => {
       await client.connect();
   
       const { issuerA, issuerB, alice, bob, charlie, daniel } = wallets;
   
       client.on('path_find', (stream) => {
           console.log(JSON.stringify(stream.alternatives, null, '  '));
       });
   
       client.request({
           command: 'path_find',
           subcommand: 'create',
           source_account: daniel.address, // Sender: Daniel
           destination_account: charlie.address, // Recipient: Charlie
           destination_amount: {
               currency: 'USD', // Currency code
               issuer: issuerA.address, // Issuer A's address
               value: '100', // Amount of A.USD Daniel wants to send to Charlie
           },
       });
   };
   
   main();

Running the Script

1. Run the following command in the command line to execute the script.

   node pathFinding.js

2. If you see logs like the following, the operation was successful.

   [
       {
           "paths_computed": [
               [
                   {
                       "account": "rstM9rxhKo4N4WEaQgQmQSPQRgZqkhHkaU", // Issuer B's address
                       "type": 1
                   },
                   {
                       "currency": "USD",
                       "issuer": "rfkJ7Uz6NrNV1FdbmKB5wepoim51KFpYQp", // Issuer A's address
                       "type": 48
                   }
               ]
           ],
           "source_amount": {
               "currency": "EUR",
               "issuer": "rf6R7pFgytT9JKjMVjKqeTv6MeDTrbNw3", // Daniel's address
               "value": "100"
           }
       }
   ]