Merge pull request #21 from near/fungible-token

Fungible token example

Author: ailisp

examples/fungible-token/README.md

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+# Fungible token contract in JavaScript
+
+This is an equivalent JavaScript implementation of the fungible token example. Every user can send and recieve a fungible token.
+
+## Build the contract
+
+First ensure JSVM contract is build and deployed locally, follow [Local Installation](https://github.com/near/near-sdk-js#local-installation). Then run:
+```
+npm i
+npm run build
+```
+
+## Test the contract with workspaces-js
+```
+npm run test
+```

examples/fungible-token/__tests__/test-fungible-token.ava.js

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+import { Worker } from 'near-workspaces';
+import {readFile} from 'fs/promises'
+import test from 'ava';
+
+// TODO: make this function part of the npm package when it is available
+function encodeCall(contract, method, args) {
+    return Buffer.concat([Buffer.from(contract), Buffer.from([0]), Buffer.from(method), Buffer.from([0]), Buffer.from(JSON.stringify(args))])
+}
+
+test.beforeEach(async t => {
+    // Init the worker and start a Sandbox server
+    const worker = await Worker.init();
+
+    // Prepare sandbox for tests, create accounts, deploy contracts, etx.
+    const root = worker.rootAccount;
+
+    // Deploy the jsvm contract.
+    const jsvm = await root.createAndDeploy(
+        root.getSubAccount('jsvm').accountId,
+        'build/jsvm.wasm',
+    );
+
+    // Deploy fungible token contract
+    const fungibleTokenContract = await root.createSubAccount('fungible-token');
+    let ftContractBase64 = (await readFile('build/fungible-token.base64')).toString();
+    await fungibleTokenContract.call(jsvm, 'deploy_js_contract', Buffer.from(ftContractBase64, 'base64'), {attachedDeposit: '400000000000000000000000'});
+    await fungibleTokenContract.call(jsvm, 'call_js_contract', encodeCall(fungibleTokenContract.accountId, 'init', ['a', '1000']), {attachedDeposit: '400000000000000000000000'});
+
+    // Create test accounts
+    const ali = await root.createSubAccount('ali');
+    const bob = await root.createSubAccount('bob');
+
+    // Save state for test runs, it is unique for each test
+    t.context.worker = worker;
+    t.context.accounts = {
+        root,
+        jsvm,
+        fungibleTokenContract,
+        ali,
+        bob,
+    };
+});
+
+test.afterEach(async t => {
+    await t.context.worker.tearDown().catch(error => {
+        console.log('Failed tear down the worker:', error);
+    });
+});
+
+test('Owner has all balance in the beginning', async t => {
+    const { jsvm, fungibleTokenContract } = t.context.accounts;
+    const result = await jsvm.view('view_js_contract', encodeCall(fungibleTokenContract.accountId, 'ftBalanceOf', [fungibleTokenContract.accountId]));
+    t.is(result, '1000');
+});
+
+test('Can transfer if balance is sufficient', async t => {
+    const { ali, jsvm, fungibleTokenContract } = t.context.accounts;
+    
+    await fungibleTokenContract.call(jsvm, 'call_js_contract', encodeCall(fungibleTokenContract.accountId, 'ftTransfer', [ali.accountId, '100']),  {attachedDeposit: '400000000000000000000000'});
+    const aliBalance = await jsvm.view('view_js_contract', encodeCall(fungibleTokenContract.accountId, 'ftBalanceOf', [ali.accountId]));
+    t.is(aliBalance, '100');
+    const ownerBalance = await jsvm.view('view_js_contract', encodeCall(fungibleTokenContract.accountId, 'ftBalanceOf', [fungibleTokenContract.accountId]));
+    t.is(ownerBalance, '900');
+});
+
+test('Cannot transfer if balance is not sufficient', async t => {
+    const { ali, bob, jsvm, fungibleTokenContract } = t.context.accounts;
+    try {
+        await ali.call(jsvm, 'call_js_contract', encodeCall(fungibleTokenContract.accountId, 'ftTransfer', [bob.accountId, '100']),  {attachedDeposit: '400000000000000000000000'});
+    } catch (e) {
+        t.assert(e.toString().indexOf('Smart contract panicked: assertion failed: The account doesn\'t have enough balance') >= 0);
+    }
+});

examples/fungible-token/ava.config.cjs

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+require('util').inspect.defaultOptions.depth = 5; // Increase AVA's printing depth
+
+module.exports = {
+  timeout: '300000',
+  files: ['**/*.ava.js'],
+  failWithoutAssertions: false,
+  extensions: ['js'],
+};

examples/fungible-token/babel.config.json

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+{
+  "plugins": [
+    "../../sdk/near-bindgen-exporter",
+    ["@babel/plugin-proposal-decorators", {"version": "legacy"}]
+  ]
+}

examples/fungible-token/build.sh

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+#!/bin/bash
+set -euo pipefail
+
+mkdir -p build
+rollup -c
+cd build
+cp ../../../jsvm.wasm .
+../../../builder.sh fungible-token.js