> ## Documentation Index
> Fetch the complete documentation index at: https://cdktn.io/docs/llms.txt
> Use this file to discover all available pages before exploring further.
# Typescript: App
> CDKTN Core API Reference for App in Typescript.
Represents a cdktn application.
## Initializers
```typescript theme={null}
import { App } from 'cdktn'
new App(config?: AppConfig)
```
| **Name** | **Type** | **Description** |
| ------------------------------------------------------------------------- | ----------------------------------------------------- | --------------- |
| config | AppConfig | configuration. |
***
### `config`Optional
* *Type:* AppConfig
configuration.
***
## Methods
| **Name** | **Description** |
| ----------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------- |
| toString | Returns a string representation of this construct. |
| with | Applies one or more mixins to this construct. |
| crossStackReference | Creates a reference from one stack to another, invoked on prepareStack since it creates extra resources. |
| synth | Synthesizes all resources to the output directory. |
***
### `toString`
```typescript theme={null}
public toString(): string
```
Returns a string representation of this construct.
### `with`
```typescript theme={null}
public with(mixins: ...IMixin[]): IConstruct
```
Applies one or more mixins to this construct.
Mixins are applied in order. The list of constructs is captured at the
start of the call, so constructs added by a mixin will not be visited.
Use multiple `with()` calls if subsequent mixins should apply to added
constructs.
#### `mixins`Required
* *Type:* ...constructs.IMixin\[]
The mixins to apply.
***
### `crossStackReference`
```typescript theme={null}
public crossStackReference(fromStack: TerraformStack, toStack: TerraformStack, identifier: string): string
```
Creates a reference from one stack to another, invoked on prepareStack since it creates extra resources.
#### `fromStack`Required
* *Type:* TerraformStack
***
#### `toStack`Required
* *Type:* TerraformStack
***
#### `identifier`Required
* *Type:* string
***
### `synth`
```typescript theme={null}
public synth(): void
```
Synthesizes all resources to the output directory.
## Static Functions
| **Name** | **Description** |
| ------------------------------------------------------------- | ----------------------------- |
| isConstruct | Checks if `x` is a construct. |
| isApp | *No description.* |
| of | *No description.* |
***
### `isConstruct`
```typescript theme={null}
import { App } from 'cdktn'
App.isConstruct(x: any)
```
Checks if `x` is a construct.
Use this method instead of `instanceof` to properly detect `Construct`
instances, even when the construct library is symlinked.
Explanation: in JavaScript, multiple copies of the `constructs` library on
disk are seen as independent, completely different libraries. As a
consequence, the class `Construct` in each copy of the `constructs` library
is seen as a different class, and an instance of one class will not test as
`instanceof` the other class. `npm install` will not create installations
like this, but users may manually symlink construct libraries together or
use a monorepo tool: in those cases, multiple copies of the `constructs`
library can be accidentally installed, and `instanceof` will behave
unpredictably. It is safest to avoid using `instanceof`, and using
this type-testing method instead.
#### `x`Required
* *Type:* any
Any object.
***
### `isApp`
```typescript theme={null}
import { App } from 'cdktn'
App.isApp(x: any)
```
#### `x`Required
* *Type:* any
***
### `of`
```typescript theme={null}
import { App } from 'cdktn'
App.of(construct: IConstruct)
```
#### `construct`Required
* *Type:* constructs.IConstruct
***
## Properties
| **Name** | **Type** | **Description** |
| ------------------------------------------------------------------------------------------ | --------------------------------------------------- | --------------------------------------------------------------- |
| node | constructs.Node | The tree node. |
| hclOutput | boolean | *No description.* |
| manifest | Manifest | *No description.* |
| outdir | string | The output directory into which resources will be synthesized. |
| skipBackendValidation | boolean | Whether to skip backend validation during synthesis of the app. |
| skipValidation | boolean | Whether to skip all validations during synthesis of the app. |
| targetStackId | string | The stack which will be synthesized. |
***
### `node`Required
```typescript theme={null}
public readonly node: Node;
```
* *Type:* constructs.Node
The tree node.
***
### `hclOutput`Required
```typescript theme={null}
public readonly hclOutput: boolean;
```
* *Type:* boolean
***
### `manifest`Required
```typescript theme={null}
public readonly manifest: Manifest;
```
* *Type:* Manifest
***
### `outdir`Required
```typescript theme={null}
public readonly outdir: string;
```
* *Type:* string
The output directory into which resources will be synthesized.
***
### `skipBackendValidation`Required
```typescript theme={null}
public readonly skipBackendValidation: boolean;
```
* *Type:* boolean
Whether to skip backend validation during synthesis of the app.
***
### `skipValidation`Required
```typescript theme={null}
public readonly skipValidation: boolean;
```
* *Type:* boolean
Whether to skip all validations during synthesis of the app.
***
### `targetStackId`Optional
```typescript theme={null}
public readonly targetStackId: string;
```
* *Type:* string
The stack which will be synthesized.
If not set, all stacks will be synthesized.
***