---
title: "Lifecycle"
slug: "081-core-lifecycle"
updated: 2025-05-23T22:34:26Z
published: 2025-05-23T22:34:26Z
canonical: "docs.developer.comcast.com/081-core-lifecycle"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://docs.developer.comcast.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Lifecycle

**Lifecycle Module 0.8.1 | Core SDK**

## Overview

Methods and events for responding to lifecycle changes in your app

## OpenRPC

Firebolt APIs are maintained in the [rdkcentral/firebolt-core-sdk](https://github.com/rdkcentral/firebolt-core-sdk) GitHub repository.

You can see this API in the [lifecycle.json](https://github.com/rdkcentral/firebolt-core-sdk/blob/main/src/modules/lifecycle.json) OpenRPC JSON-Schema document.

## Usage

To use the Lifecycle module, you can import it into your project from the Firebolt SDK:

```
import { Lifecycle } from '@firebolt-js/sdk'
```

## Methods

### close

Request that the platform move your app out of focus

```
function close(reason: CloseReason): Promise<void>
```

Parameters:

| Param | Type | Required | Summary |
| --- | --- | --- | --- |
| `reason` | [`CloseReason`](/docs/081-core-Lifecycle-schemas#closereason) | true | The reason the app is requesting to be closed |

Promise resolution:

```
void
```

**Examples**

Close the app when the user presses back on the app home screen

JavaScript:

```
import { Lifecycle } from '@firebolt-js/sdk'

Lifecycle.close("remoteButton")
    .then(success => {
        console.log(success)
    })
```

Value of `success`:

```
null
```

**JSON-RPC:**

Request:

```
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "lifecycle.close",
  "params": {
    "reason": "remoteButton"
  }
}
```

Response:

```
{
  "jsonrpc": "2.0",
  "id": 1,
  "result": null
}
```

**More examples...**

    
Close the app when the user selects an exit menu item

JavaScript:

```
import { Lifecycle } from '@firebolt-js/sdk'

Lifecycle.close("userExit")
    .then(success => {
        console.log(success)
    })
```

Value of `success`:

```
null
```

**JSON-RPC:**

Request:

```
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "lifecycle.close",
  "params": {
    "reason": "userExit"
  }
}
```

Response:

```
{
  "jsonrpc": "2.0",
  "id": 1,
  "result": null
}
```

---

### finished

Notify the platform that the app is done unloading

```
function finished(): Promise<void>
```

Promise resolution:

```
void
```

**Examples**

Default Example

JavaScript:

```
import { Lifecycle } from '@firebolt-js/sdk'

Lifecycle.finished()
    .then(results => {
        console.log(results)
    })
```

Value of `results`:

```
null
```

**JSON-RPC:**

Request:

```
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "lifecycle.finished",
  "params": {}
}
```

Response:

```
{
  "jsonrpc": "2.0",
  "id": 1,
  "result": null
}
```

---

### listen

Listen for events from this module.

To listen to a specific event pass the event name as the first parameter:

```
Lifecycle.listen(event: string, (data: any) => void): Promise<number>
```

Parameters:

| Param | Type | Required | Summary |
| --- | --- | --- | --- |
| `event` | `string` | Yes | The event to listen for, see [Events](/docs/081-core-lifecycle#events). |
| *callback* | `function` | Yes | A function that will be invoked when the event occurs. |

Promise resolution:

| Type | Description |
| --- | --- |
| `number` | Listener ID to clear the callback method and stop receiving the event, e.g. `Lifecycle.clear(id)` |

Callback parameters:

| Param | Type | Required | Summary |
| --- | --- | --- | --- |
| `data` | `any` | Yes | The event data, which depends on which event is firing, see [Events](/docs/081-core-lifecycle#events). |

To listen to all events from this module pass only a callback, without specifying an event name:

```
Lifecycle.listen((event: string, data: any) => void): Promise<number>
```

Parameters:

| Param | Type | Required | Summary |
| --- | --- | --- | --- |
| *callback* | `function` | Yes | A function that will be invoked when the event occurs. The event data depends on which event is firing, see [Events](/docs/081-core-lifecycle#events). |

Callback parameters:

| Param | Type | Required | Summary |
| --- | --- | --- | --- |
| `event` | `string` | Yes | The event that has occured listen for, see [Events](/docs/081-core-lifecycle#events). |
| `data` | `any` | Yes | The event data, which depends on which event is firing, see [Events](/docs/081-core-lifecycle#events). |

Promise resolution:

| Type | Description |
| --- | --- |
| `number` | Listener ID to clear the callback method and stop receiving the event, e.g. `Lifecycle.clear(id)` |

See [Listening for events](/docs/listening-for-events/) for more information and examples.

---

### once

Listen for only one occurance of an event from this module. The callback will be cleared after one event.

To listen to a specific event pass the event name as the first parameter:

```
Lifecycle.once(event: string, (data: any) => void): Promise<number>
```

Parameters:

| Param | Type | Required | Summary |
| --- | --- | --- | --- |
| `event` | `string` | Yes | The event to listen for, see [Events](/docs/081-core-lifecycle#events). |
| *callback* | `function` | Yes | A function that will be invoked when the event occurs. |

Promise resolution:

| Type | Description |
| --- | --- |
| `number` | Listener ID to clear the callback method and stop receiving the event, e.g. `Lifecycle.clear(id)` |

Callback parameters:

| Param | Type | Required | Summary |
| --- | --- | --- | --- |
| `data` | `any` | Yes | The event data, which depends on which event is firing, see [Events](/docs/081-core-lifecycle#events). |

To listen to all events from this module pass only a callback, without specifying an event name:

```
Lifecycle.once((event: string, data: any) => void): Promise<number>
```

Parameters:

| Param | Type | Required | Summary |
| --- | --- | --- | --- |
| *callback* | `function` | Yes | A function that will be invoked when the event occurs. The event data depends on which event is firing, see [Events](/docs/081-core-lifecycle#events). |

Callback parameters:

| Param | Type | Required | Summary |
| --- | --- | --- | --- |
| `event` | `string` | Yes | The event that has occured listen for, see [Events](/docs/081-core-lifecycle#events). |
| `data` | `any` | Yes | The event data, which depends on which event is firing, see [Events](/docs/081-core-lifecycle#events). |

Promise resolution:

| Type | Description |
| --- | --- |
| `number` | Listener ID to clear the callback method and stop receiving the event, e.g. `Lifecycle.clear(id)` |

See [Listening for events](/docs/listening-for-events/) for more information and examples.

---

### ready

Notify the platform that the app is ready

```
function ready(): Promise<void>
```

Promise resolution:

```
void
```

**Examples**

Let the platform know that your app is ready

JavaScript:

```
import { Lifecycle } from '@firebolt-js/sdk'

Lifecycle.ready()
    .then(result => {
        console.log(result)
    })
```

Value of `result`:

```
null
```

**JSON-RPC:**

Request:

```
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "lifecycle.ready",
  "params": {}
}
```

Response:

```
{
  "jsonrpc": "2.0",
  "id": 1,
  "result": null
}
```

---

### state

Get the current state of the app. This function is **synchronous**.

```
function state(): LifecycleState
```

Promise resolution:

| Type | Description |
| --- | --- |
| [`LifecycleState`](/docs/081-core-Lifecycle-schemas#lifecyclestate) | The application lifecycle state |

**Examples**

Default Example

JavaScript:

```
import { Lifecycle } from ''

const state = Lifecycle.state()
console.log(state)
```

Value of `state`:

```
"foreground"
```

**JSON-RPC:**

Request:

```
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "lifecycle.state",
  "params": {}
}
```

Response:

```
{
  "jsonrpc": "2.0",
  "id": 1,
  "result": "foreground"
}
```

---

## Events

### background

Listen to the background event

See also: [listen()](/docs/081-core-lifecycle#listen), [once()](/docs/081-core-lifecycle#listen), [clear()](/docs/081-core-lifecycle#listen).

Event value:

| Type | Description |
| --- | --- |
| [`LifecycleEvent`](/docs/081-core-lifecycle#lifecycleevent) | A an object describing the previous and current states |

**Examples**

Default Example:

JavaScript:

```
import { Lifecycle } from '@firebolt-js/sdk'

Lifecycle.listen('background', value => {
  console.log(value)
})
```

Value of `value`

```
{
  "state": "background",
  "previous": "foreground"
}
```

**JSON-RPC:**

Request:

```
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "lifecycle.onBackground",
  "params": {
    "listen": true
  }
}
```

Response:

```
{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "state": "background",
    "previous": "foreground"
  }
}
```

---

### foreground

Listen to the foreground event

See also: [listen()](/docs/081-core-lifecycle#listen), [once()](/docs/081-core-lifecycle#listen), [clear()](/docs/081-core-lifecycle#listen).

Event value:

| Type | Description |
| --- | --- |
| [`LifecycleEvent`](/docs/081-core-lifecycle#lifecycleevent) | A an object describing the previous and current states |

**Examples**

Default Example:

JavaScript:

```
import { Lifecycle } from '@firebolt-js/sdk'

Lifecycle.listen('foreground', value => {
  console.log(value)
})
```

Value of `value`

```
{
  "state": "foreground",
  "previous": "inactive"
}
```

**JSON-RPC:**

Request:

```
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "lifecycle.onForeground",
  "params": {
    "listen": true
  }
}
```

Response:

```
{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "state": "foreground",
    "previous": "inactive"
  }
}
```

**More examples...**

    
Move to foreground via remote branded buton:

JavaScript:

```
import { Lifecycle } from '@firebolt-js/sdk'

Lifecycle.listen('foreground', value => {
  console.log(value)
})
```

Value of `value`

```
{
  "state": "foreground",
  "previous": "inactive",
  "source": "remote"
}
```

**JSON-RPC:**

Request:

```
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "lifecycle.onForeground",
  "params": {
    "listen": true
  }
}
```

Response:

```
{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "state": "foreground",
    "previous": "inactive",
    "source": "remote"
  }
}
```

---

### inactive

Listen to the inactive event

See also: [listen()](/docs/081-core-lifecycle#listen), [once()](/docs/081-core-lifecycle#listen), [clear()](/docs/081-core-lifecycle#listen).

Event value:

| Type | Description |
| --- | --- |
| [`LifecycleEvent`](/docs/081-core-lifecycle#lifecycleevent) | A an object describing the previous and current states |

**Examples**

Default Example:

JavaScript:

```
import { Lifecycle } from '@firebolt-js/sdk'

Lifecycle.listen('inactive', value => {
  console.log(value)
})
```

Value of `value`

```
{
  "state": "inactive",
  "previous": "initializing"
}
```

**JSON-RPC:**

Request:

```
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "lifecycle.onInactive",
  "params": {
    "listen": true
  }
}
```

Response:

```
{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "state": "inactive",
    "previous": "initializing"
  }
}
```

---

### suspended

Listen to the suspended event

See also: [listen()](/docs/081-core-lifecycle#listen), [once()](/docs/081-core-lifecycle#listen), [clear()](/docs/081-core-lifecycle#listen).

Event value:

| Type | Description |
| --- | --- |
| [`LifecycleEvent`](/docs/081-core-lifecycle#lifecycleevent) | A an object describing the previous and current states |

**Examples**

Default Example:

JavaScript:

```
import { Lifecycle } from '@firebolt-js/sdk'

Lifecycle.listen('suspended', value => {
  console.log(value)
})
```

Value of `value`

```
{
  "state": "suspended",
  "previous": "inactive"
}
```

**JSON-RPC:**

Request:

```
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "lifecycle.onSuspended",
  "params": {
    "listen": true
  }
}
```

Response:

```
{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "state": "suspended",
    "previous": "inactive"
  }
}
```

---

### unloading

Listen to the unloading event

See also: [listen()](/docs/081-core-lifecycle#listen), [once()](/docs/081-core-lifecycle#listen), [clear()](/docs/081-core-lifecycle#listen).

Event value:

| Type | Description |
| --- | --- |
| [`LifecycleEvent`](/docs/081-core-lifecycle#lifecycleevent) | A an object describing the previous and current states |

**Examples**

Default Example:

JavaScript:

```
import { Lifecycle } from '@firebolt-js/sdk'

Lifecycle.listen('unloading', value => {
  console.log(value)
})
```

Value of `value`

```
{
  "state": "unloading",
  "previous": "inactive"
}
```

**JSON-RPC:**

Request:

```
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "lifecycle.onUnloading",
  "params": {
    "listen": true
  }
}
```

Response:

```
{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "state": "unloading",
    "previous": "inactive"
  }
}
```

---

## Schemas

### LifecycleEvent

A an object describing the previous and current states

```
type LifecycleEvent = {
  state: LifecycleState        // The application lifecycle state
  previous: LifecycleState     // The application lifecycle state
  source?: 'voice' | 'remote'  // The source of the lifecycle change.
}
```

See also:

- [LifecycleState](/docs/081-core-Lifecycle-schemas#lifecyclestate)

---