vexjs

Javascript API for integration with Vexanium-based blockchains using Vexanium RPC API.

Documentation can be found here

Installation

NPM

The official distribution package can be found at npm.

Add dependency to your project

yarn add vexjs

Using with Typescript

In order to get access to the TextEncoding and TextDecoding types, you need to add @types/text-encoding as a dev dependency: yarn add --dev @types/text-encoding

If you're using Node (not a browser) then you'll also need to make sure the dom lib is referenced in your tsconfig.json:

{
	"compilerOptions": {
		"lib": [..., "dom"]
	}
}

Browser Distribution

Clone this repository locally then run yarn build-web. The browser distribution will be located in dist-web and can be directly copied into your project repository. The dist-web folder contains minified bundles ready for production, along with source mapped versions of the library for debugging. For full browser usage examples, see the documentation.

Import

ES Modules

Importing using ESM syntax is supported using TypeScript, webpack, or Node.js with --experimental-modules flag

import { Api, JsonRpc, RpcError } from 'vexjs';
import { JsSignatureProvider } from 'vexjs/dist/vexjs-jssig';           // development only

CommonJS

Importing using commonJS syntax is supported by Node.js out of the box.

const { Api, JsonRpc, RpcError } = require('vexjs');
const { JsSignatureProvider } = require('vexjs/dist/vexjs-jssig');      // development only
const fetch = require('node-fetch');                                    // node only; not needed in browsers
const { TextEncoder, TextDecoder } = require('util');                   // node only; native TextEncoder/Decoder

Basic Usage

Signature Provider

The Signature Provider holds private keys and is responsible for signing transactions.

Using the JsSignatureProvider in the browser is not secure and should only be used for development purposes. Use a secure vault outside of the context of the webpage to ensure security when signing transactions in production

const defaultPrivateKey = "5JtUScZK2XEp3g9gh7F8bwtPTRAkASmNrrftmx4AxDKD5K4zDnr"; // bob
const signatureProvider = new JsSignatureProvider([defaultPrivateKey]);

JSON-RPC

Open a connection to JSON-RPC, include fetch when on Node.js.

const rpc = new JsonRpc('http://127.0.0.1:8888', { fetch });

API

Include textDecoder and textEncoder when using in Node. You may exclude these when running in a browser since most modern browsers now natively support these. If your browser does not support these (https://caniuse.com/#feat=textencoder), then you can import them as a dependency through the following deprecated npm package: https://www.npmjs.com/package/text-encoding

const api = new Api({ rpc, signatureProvider, textDecoder: new TextDecoder(), textEncoder: new TextEncoder() });

Sending a transaction

transact() is used to sign and push transactions onto the blockchain with an optional configuration object parameter. This parameter can override the default value of broadcast: true, and can be used to fill TAPOS fields given expireSeconds and either blocksBehind or useLastIrreversible. Given no configuration options, transactions are expected to be unpacked with TAPOS fields (expiration, ref_block_num, ref_block_prefix) and will automatically be broadcast onto the chain.

(async () => {
  const result = await api.transact({
    actions: [{
      account: 'vex.token',
      name: 'transfer',
      authorization: [{
        actor: 'useraaaaaaaa',
        permission: 'active',
      }],
      data: {
        from: 'useraaaaaaaa',
        to: 'useraaaaaaab',
        quantity: '0.0001 SYS',
        memo: '',
      },
    }]
  }, {
    blocksBehind: 3,
    expireSeconds: 30,
  });
  console.dir(result);
})();

Error handling

use RpcError for handling RPC Errors

...
try {
  const result = await api.transact({
  ...
} catch (e) {
  console.log('\nCaught exception: ' + e);
  if (e instanceof RpcError)
    console.log(JSON.stringify(e.json, null, 2));
}
...

Contributing

Contributing Guide

Code of Conduct

License

MIT

Important

See LICENSE for copyright and license terms.

All repositories and other materials are provided subject to the terms of this IMPORTANT notice and you must familiarize yourself with its terms. The notice contains important information, limitations and restrictions relating to our software, publications, trademarks, third-party resources, and forward-looking statements. By accessing any of our repositories and other materials, you accept and agree to the terms of the notice.