Parameterized Templates

When templates are used as building blocks, the topology context of the parent element is passed to the child template. A template can also receive further configuration from the parent element if you define configuration parameters (props). The values that you specify for props in the parent element are then used to modify the building block of the parameterized template. The parameterized template itself contains this modification logic in the form of a JSONata expression with is located under the key preprocess.

This expression receives the template element of the parameterized template as input as well as the props. The values of the props declared in the parameterized template are default values, which are used if not specified by the parent template. The result of the expression then replaces the template element before it is used in the rendering process.

Example:

{
  "name": "mysolution:exampleParameterizedTemplate",
  "props": {
    "customContent": "element at position 1"
  },
  "preprocess": "$ ~> |elements[1].element|{ \"content\": $props.customContent }|",
  "element": {
    "instanceOf": "elements",
    "elements": [
      {
        "instanceOf": "text",
        "content": "element at position 0"
      },
      {
        "instanceOf": "html",
        "element": {
          "instanceOf": "text"
          ...
        }
      }
    ]
  }
}

Preprocess receives the following bindings:

• $: The root element
• $props: The result of merging the declared props with the passed props { ...declaredProps, ...passedProps }

Using a Parameterized Template as a Building Block

The parent template specifies the values for the props of a parameterized template in the same way as it does for atomic building blocks:

"element": {
  "instanceof": "mysolution:exampleParameterizedTemplate",
  "customContent": ""
}