Feather.js is a JavaScript SDK for writing applications that interact with the Terra blockchain from either Node.js, browser, or React Native environments and provides simple abstractions over core data structures, serialization, key management, and API request generation.

Features

• Written in TypeScript, with type definitions
• Versatile support for key management solutions
• Works in Node.js, in the browser, and React Native
• Exposes the Terra API through LCDClient
• Parses responses into native JavaScript types

We highly suggest using Feather.js with TypeScript, or JavaScript in a code editor that has support for type declarations, so you can take advantage of the helpful type hints that are included with the package.

Installation

Grab the latest version off NPM:

npm install @terra-money/feather.js

Usage

Feather.js can be used in Node.js, as well as inside the browser. Please check the docs for notes on how to get up and running.

Getting blockchain data

import { LCDClient, Coin } from '@terra-money/feather.js';

// connect to testnet
const lcd = LCDClient.fromDefaultConfig('testnet');

// connect to mainnet
const lcd = LCDClient.fromDefaultConfig('mainnet');

// To use LocalTerra or a custom endpoint
const lcd = new LCDClient({
  localterra: {
    // key must be the chainID
    lcd: 'http://localhost:1317',
    chainID: 'localterra',
    gasAdjustment: 1.75,
    gasPrices: { uluna: 0.15 },
    prefix: 'terra', // bech32 prefix, used by the LCD to understand which is the right chain to query
  },
});

// get the current balance of `terra1x46rqay4d3cssq8gxxvqz8xt6nwlz4td20k38v`
// LCD understand automatically the chain to query using the bech32 prefix of the address
const balance = lcd.bank.balance(
  'terra1x46rqay4d3cssq8gxxvqz8xt6nwlz4td20k38v'
);
console.log(balance);

// get the total circulation supply
// LCD needs a chainID to understand the chain it should query
const total = lcd.bank.total('phoenix-1');
console.log(total);

Broadcasting transactions

First, get some testnet tokens for terra1x46rqay4d3cssq8gxxvqz8xt6nwlz4td20k38v, or use LocalTerra.

import { LCDClient, MsgSend, MnemonicKey } from '@terra-money/feather.js';

// create a key out of a mnemonic
const mk = new MnemonicKey({
  mnemonic:
    'notice oak worry limit wrap speak medal online prefer cluster roof addict wrist behave treat actual wasp year salad speed social layer crew genius',
});

// connect to testnet
const lcd = LCDClient.fromDefaultConfig('testnet');

// a wallet can be created out of any key
// wallets abstract transaction building
const wallet = lcd.wallet(mk);

// create a simple message that moves coin balances
const send = new MsgSend(
  mk.accAddress('terra'), // .accAddress is now a function which require the prefix as parameter
  'terra17lmam6zguazs5q5u6z5mmx76uj63gldnse2pdp',
  { uluna: 1200000 }
);

wallet
  .createAndSignTx({
    msgs: [send],
    memo: 'test from feather.js!',
    chainID: 'pisco-1', // now here a chainID must be specified
  })
  .then(tx => lcd.tx.broadcast(tx, 'pisco-1')) // same here
  .then(result => {
    console.log(`TX hash: ${result.txhash}`);
  });

Tx with messages from custom modules

wallet
  // feather js detect that the tx contains a MsgAminoCustom and will use SIGN_MODE_AMINO_JSON instead of SIGN_MODE_DIRECT
  .createAndSignTx({
    msgs: [
      new MsgAminoCustom({
        type: 'osmosis/gamm/swap-exact-amount-in',
        value: {
          sender: 'osmo1...',
          routes: [
            {
              pool_id: '2',
              token_out_denom: 'uion',
            },
          ],
          token_in: {
            denom: 'uosmo',
            amount: '10000000',
          },
          token_out_min_amount: '8538',
        },
      }),
      // you can add more messages here if needed
    ],
    memo: 'test from feather.js!',
    chainID: 'osmosis-1',
  })
  .then(tx => lcd.tx.broadcast(tx, 'osmosis-1'))
  .then(result => {
    console.log(`TX hash: ${result.txhash}`);
  });

Feather.js in the browser

You can access all the objects of the @terra-money/feather.js from the global Feather object if you load Feather.js with a <script> tag.

Include the following in your browser:

<script
  crossorigin
  src="https://unpkg.com/@terra-money/feather.js/dist/bundle.js"
></script>

You can find a small JSFiddle example that refreshes current Oracle votes here.

Feather.js in React Native

In order to use Feather.js inside React Native, you need to add the node-libs-react-native package and react-native-get-random-values package to your React Native app's package.json.

yarn add node-libs-react-native react-native-get-random-values

You will need to register Node.js native modules in an entry point of your application, such as index.tsx:

import 'node-libs-react-native/globals';
import 'react-native-get-random-values';

Also, add resolvers to your metro.config.js

module.exports {
  // ...
  resolver: {
    // ...
    extraNodeModules: require('node-libs-react-native'),
  },
  // ...
}

License

This software is licensed under the MIT license. See LICENSE for full disclosure.

© 2022 Terraform Labs, PTE.