call

Calls a JavaScript function through the web component.

Syntax

ui.Interface.frontCall("webcomponent", "call",
  [aui-name, function-name [, param1, param2, ... ] ],
  [result]
)
  1. aui-name - This is the name of the web component name in the AUI tree.
  2. function-name - This is the name of a user-defined JavaScript function to be called.
  3. param1, param2, ... - Optional parameters to be passed to the web component JavaScript function.
  4. result - Holds the JavaScript function return value.

Usage

This front call executes a JavaScript function of the WEBCOMPONENT form field identified by aui-name.

Important: Use the webcomponent.call front call only for specific needs: With desktop and web front ends, a front call implies a network roundtrip and abstract user interface update that may cause unwanted delays. Prefer using gICAPI interface triggers such as onData / onProperty instead.

The JavaScript function identified by function-name must be implemented in the HTML content pointed by the URL-based web component, or in the user-defined JavaScript of a gICAPI-based web component.

Important: The function specified in the webcomponent.call front call must be a user-defined function. Calling directly JavaScript API methods such as window.alert() is not supported. To call the window.alert() method, implement a wrapper that calls the window method.

The arguments following the function-name argument will be passed to the JavaScript function.

The result variable will contain the value returned by the JavaScript function.

When using simple data types in arguments, values are passed as is to the JavaScript function of the web component. When using RECORD or DYNAMIC ARRAY types, the runtime system converts the structured data to a JSON string. Similarly, if the JavaScript function returns a complex data structure in JSON notation, it must be used to assign a RECORD or DYNAMIC ARRAY.

For more details about JSON notation usage for complex data types, see the ui.Interface.frontCall() method.

Example 1: Using a simple string parameter and return value:

DEFINE result STRING
CALL ui.Interface.frontCall("webcomponent","call",
        ["formonly.mywebcomp","echoString","abcdef"],[result])

Example 2: Using structured variables to be converted to JSON for the JavaScript code:

DEFINE options RECORD
          filter STRING,
          creation DATE
       END RECORD,
       items DYNAMIC ARRAY OF STRING
LET options.filter = "abc*"
LET options.creation = TODAY
CALL ui.Interface.frontCall("webcomponent","call",
        ["formonly.mywebcomp","getItems", options ],
        [ items ])

For a complete example, see Example 1: Calling a JavaScript function.