Using the Declarative API

Objective

After completing this lesson, you will be able to embed components declaratively in HTML pages

Declarative API for Initial Components

With the declarative sap/ui/core/ComponentSupport API, it is possible to define the initially started component directly in the HTML markup. This provides an alternative to the imperative way with JavaScript.

The declarative component support is not activated by default but must be enabled via the bootstrap. To do this, the following attribute must be added to the bootstrap script to load the ComponentSupport module (see the figure Using the Declarative API):

Code Snippet
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data-sap-ui-onInit="module:sap/ui/core/ComponentSupport"

The run function of sap/ui/core/ComponentSupport is called automatically once the module has been loaded. It scans the DOM for HTML elements containing a special data attribute named data-sap-ui-component. All DOM elements marked with this data attribute will be regarded as container elements into which a sap/ui/core/ComponentContainer is inserted.

Additional data attributes are then used to define the constructor arguments of the created component container instance. In the example shown, the following data attributes are specified:

  • data-id

    This attribute is used to pass the Id for the component container instance to be created.

  • data-name

    The data-name attribute contains the name of the component to be instantiated.

  • data-settings

    The object specified for the data-settings attribute is passed to the component instance when it is created. In the example, it is used to set the component instance Id.

Note

The ComponentSupport module enforces asynchronous module loading of the component with "manifest first". This means that the manifest.json file is loaded before evaluating the component to optimize loading behavior (see above).

Define the Initially Started Component Directly in the HTML Markup

Business Scenario

In this exercise, you use the declarative API for initial components to declare the component defined in the previous exercise in the <body> of the HTML page. This automatically instantiates the component through the framework and embeds it in the HTML page. The coding from the previous exercise that instantiated the component and placed it on the HTML page is then no longer required and is deleted.

Template:Git Repository: https://github.com/SAP-samples/sapui5-development-learning-journey.git, Branch: sol/6_components
Model solution:Git Repository: https://github.com/SAP-samples/sapui5-development-learning-journey.git, Branch: sol/7_declarative_API_for_components

Task 1: Remove the Instantiation of the Component

Steps

  1. Delete the index.js module from the webapp folder.

    1. Open the context menu for the index.js file in the project structure.

    2. Select Delete.

    3. Confirm the Move File to Trash dialog with OK.

Task 2: Declare the Component in the <body> of the HTML Page

Steps

  1. Make sure that the index.html page is open in the editor.

  2. Delete the following attribute from the bootstrap script as the index.js module was deleted in the previous step:

    Code Snippet
    1
    data-sap-ui-onInit="module:sap/training/exc/index"

  3. Add the following attribute to the bootstrap script to enable the ComponentSupport module:

    Code Snippet
    1
    data-sap-ui-onInit="module:sap/ui/core/ComponentSupport"

    Result

    The bootstrap script should now look like this:

  4. Add the following <div> tag to the <body> of the HTML page to instantiate the component when the onInit event is fired:

    Code Snippet
    123456
    <div
    data-sap-ui-component
    data-id="container"
    data-name="sap.training.exc"
    data-settings='{"id" : "sap.training.exc"}'
></div>

    Result

    The <body> of the HTML page should now look like this:

  5. Test run your application by starting it from the SAP Business Application Studio.

    1. Right-click on any subfolder in your sapui5-development-learning-journey project and select Preview Application from the context menu that appears.

    2. Select the npm script named start-noflp in the dialog that appears.

    3. In the opened application, check if the component is displayed with the App view as the root view.

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