Object

Actions are written in standard JavaScript, but development requires the use of an action-specific object. An object is structural data that holds data. Objects include $ui and $const, which have preregistered properties, and $param and $session, to which properties can be added arbitrarily. There is also $req and $res which can only be used in REST API actions.

Object	Purpose	Description
$ui	Access to UI components	Can set/get values for registered properties
$param	Data transfer to the next ui	Can set/get any property
$session	Data transfer during a session	Can set/get any property
$const	Constant Reference	Possible to retrieve registered constant values
$req	Request data	Obtain HTTP request object in REST API action
$res	Response data	Set HTTP response object in REST API action

Tips

Tips

Names of objects and functions that the service prepares in advance are marked with "$".

$ui

$ui is an object that represents the UI that defines the action. components placed in the UI can be retrieved as property values. It also indicates the state of the component as it appears in the UI after the action is executed.

Obtaining component values during action execution	Example: const val = $ui.text_field_1.value;
Set component values after action execution	Example: $ui.text_field_1.value = val;

The above shows an example of getting the value of a text field when an action is executed and an example of setting the value of a text field after the action is executed.

A component has not only a value, but also various other properties such as color, variants, etc. that decorate the component. They can be acquired/configured in the same way in the action.

Tips

Tips

• In $ui object, $this object can be used.
• When an action gets its own property value, the description of "$ui.componentID.propertyName" and "$ui.$this.propertyName" will have the same behavior.

$this

$this is an object that indicates the component that is executing the action. It can be used to obtain the property value of the component itself that is placed in the UI.

The available properties vary depending on the part, so they may not exist depending on the component that performed the action.

It is also possible to use functions that can be used commonly within an application, such as global functions. In the action of the component with ID "text_field_1", you can replace it with $this without entering the component ID, such as $ui.text_field_1.value.

Tips

Tips

• If you define $this, code assist for the component property that is the launch source will be displayed and you can write the action.
• When using $this in the action of the app bar, icon button, avatar, breadcrumb list, or bottom navigation part, undefined is returned, so by using the optional chain operator, such as $ui.$this?.value, an error will not occur even if it is undefined.

$param

$param is a parameter object that sends arbitrary data to the next UI screen. Scope is up to the next UI screen. You can add any property in $param as follows

$param.name = “Adam”;
$param.age = 26;

You can receive $param in the onload action of the target UI.

const name = $param.name;
const age = $param.age;

Tips

Tips

• Note that an error will occur if the memory limit in the action is reached when setting data in $param.
• URL parameters can be received as "$param.parameter name".
  For example, if the parameter name is "id", the parameter value can be received in "$param.id".
  For more information on passing URL parameters, please see the Application URL tips.

$session

$session is a session object that manages arbitrary data during a session. The scope is the duration of the session. Arbitrary properties can be added and retrieved as well as parameters.

Tips

Tips

• Cookies are required for session use. Please check your browser settings.
• Note that an error will occur if the memory limit in the action is reached when setting data in $session.
• When Buffer type data is set in $session, it is stored as JSON (text data) such as [{”data“:{”type“: ‘Buffer’, ‘data’:[0, 1, …]}, ‘filename’: ‘xxxxxx.xxx’, ‘filesize’:xxxxxx}].
  To treat the stored data as Buffer type data, the value of the data key must be obtained from $session and converted to Buffer.

Session Duration

For authentication applications
Session duration is during the sign-in period.

Tips

Tips

• Please note that if you sign in with a different browser than the one you are already signed in with, the session object of the browser you are already signed in with will be discarded.
• If a session object is defined before authentication, it can be inherited by the session object after authentication.

For unauthenticated applications
The duration of a session can be up to 24 hours from the time the application is displayed. However, even within the duration of the session, it becomes invalid when the browser is closed.

$global

$global is an object for referencing the global functions you created. You can use global functions that are managed within your application. Example) const result = await $global.myFunction()

$const

$const is an object for referencing registered constants. You can retrieve the constant value using the name of the constant managed in the application. Example）$ui.nameField.label = $const.nameLabel;

Tips

Tips

Constant values cannot be updated.

$req

$req is an HTTP request object that can be used within a REST API action. Use the $req object to retrieve request data.
Refer to the Amazon Gateway API page for more information on the properties of the $req object.

Property	Type
body	string
headers	Object
httpMethod	string
isBase64Encoded	boolean
multiValueHeaders	Object
multiValueQueryStringParameters	Object
Path	string
pathParameters	Object
queryStringParameters	Object
requestContext	Object
resource	string
stageVariables	Object

$res

$res is an HTTP response object that can be used within a REST API action. Use the $res object to set the response data to be returned.
Refer to the Amazon Gateway API page for more information on the properties of the $res object.

Property	Type
body	string
headers	Object
isBase64Encoded	boolean
multiValueHeaders	Object
statusCode	number