Function trigger

• 1 minute to read

This non-visual widget is used to execute synchronous or async functions when the input parameters change.

General info

• type: function-trigger

Params

• arguments - an array of parameters, change of which should trigger specified callbacks.
• callback - a function ("{{#function <expression>}}") or an array of functions that are executed when the arguments change.
• catch - a function ("{{#function <expression>}}") or an array of functions that are executed if the callback fails.
• enabled - if false, the callback will not be executed. The default value is true.
• finally - a function ("{{#function <expression>}}") or an array of functions that are executed after the callback, regardless of its outcome.
• lock - names of widgets that should be locked while waiting for the callback. The editor will display a preloader on this widget.

Example

Now, let's see how you can handle the result of selecting an option. Once an option is changed, the function-trigger widget will output its title to the console.

{
  "widgets": [
    {
      "name": "options",
      "type": "option",
      "params": {
          "type": "list",
          "title": "Name",
          "prompt": "Choose a name",
          "values": [
              { "title": "Jack" },
              { "title": "James" },
              { "title": "John" }
          ]
      }
    },
    {
      "name": "option-titles",
      "type": "function-trigger",
      "enabled": false,
      "lock": [],
      "params": {
        "arguments": [
          "{{ $['options']._.title }}",
          "{{ $['options']._.title }}"
        ],
        "callback": [
          "{{ #function(var1,var2) console.log(var1,var2) }}"
        ],
        "catch": [
          "{{ #function console.error('failed') }}"
        ],
        "finally": [
          "{{ #function console.log('cleanup') }}"
        ]
      }
    }
  ]
}

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You can find more details about the properties of this widget in AuWidgetFunctionTrigger.

For more details about configuration parameters, refer to IAuWidgetFunctionTriggerConfig.