@signumjs/monitor/README.md

Monitor transactions on Signum Network blockchain

# @signumjs/monitor

A monitor to watch for specific changes on the Signum blockchain platform

Due to average blocktime of 240 seconds, transactions stay pending for a certain time. It is a repeating pattern
to watch for such changes and waiting for confirmation. This package simplifies this task.

## Installation

`@signumjs/monitor` can be used with NodeJS or Web. Two formats are available

### Using with NodeJS and/or modern web frameworks

Install using [npm](https://www.npmjs.org/):

```
npm install @signumjs/monitor
```

or using [yarn](https://yarnpkg.com/):

``` yarn
yarn add @signumjs/monitor
```

#### Example

// TODO:

```js
import {Monitor} from '@signumjs/monitor'
import {composeApi} from "@signumjs/core";

// A method that checks if an account exists
// > IMPORTANT: Do not use closures, when you need to serialize the monitor
async function tryFetchAccount() {
    const api = composeApi({ nodeHost: 'https://testnet.signum.network:6876/'})
    try{
        const {account} = await api.account.getAccount('1234')
        return account;
    }catch (e){
        // ignore error
        return null;
    }
}

// A comparing function to check if a certain condition for the returned data from fetch function
// is true. If it's true the monitor stops
function checkIfAccountExists(account) {
    return account !== null;
}

// Create your monitor
const monitor = new Monitor({
    asyncFetcherFn: tryFetchAccount,
    compareFn: checkIfAccountExists,
    intervalSecs: 10, // polling interval in seconds
    key: 'monitor-account',
    timeoutSecs: 2 * 240 // when reached timeout the monitor stops
});
// starts monitor
monitor.start();

// called when `checkIfAccountExists` returns true
monitor.onFulfilled(() => {
    console.log('Yay, account active');
});

// called when `timeoutSecs` is reached
monitor.onTimeout(() => {
    console.log('Hmm, something went wrong');
});

```

### Using in classic `<script>`

Each package is available as bundled standalone library using UMD.
This way _signumJS_ can be used also within `<script>`-Tags.
This might be useful for Wordpress and/or other PHP applications.

Just import the package using the HTML `<script>` tag.

`<script src='https://cdn.jsdelivr.net/npm/@signumjs/monitor/dist/signumjs.monitor.min.js'></script>`

#### Example

```js
const {Monitor} = sig$Monitor;
const monitor = new Monitor({
    //...
});
monitor.start()
monitor.onFulFilled(() => {
    //...
})
```

See more here:

[@signumjs/monitor Online Documentation](https://signum-network.github.io/signumjs/modules/monitor.html)