AD0-E720 Adobe Commerce Front-End Developer Expert Questions and Answers

The best way to customize a template file from a third-party module is to create a new theme that inherits from the parent theme and override the template file in the app/design/frontend/Custom/Theme/Vendor_Module/templates directory. This way, the customization is isolated from the original module and can be applied to a specific website or store view. Creating another layout file or a new module would not be as simple or flexible as creating a new theme. References: Frontend development guide, [Create a theme], [Theme inheritance]

To initialize a JavaScript component using a data attribute, the developer should use the data-mage-init attribute. This attribute allows the developer to specify the name and configuration of the component in a JSON format. For example:

This will initialize the nav component from the Vendor_Module/js/nav file with the given options. The data-bind and data-init attributes are not valid and will not work, as they are not supported by Magento. References: [JavaScript initialization], [data-mage-init]

To pass JSON data to a JavaScript component while keeping XSS prevention strategies in mind, the developer should use the following options:

• Option A: Use the x-magento-init script tag with the data-mage-init attribute and the JSON.parse function to initialize the component with the JSON data. This option is secure because it does not use any HTML tags or attributes that can be exploited by XSS attacks.
• Option C: Use the text/x-magento-init script tag with the type attribute and the JSON.parse function to initialize the component with the JSON data. This option is secure because it does not use any HTML tags or attributes that can be exploited by XSS attacks.

The following options are not secure and should not be used:

• Option B: Use the script tag with the type attribute and the escapeHtmlAttr function to initialize the component with the JSON data. This option is not secure because it uses the escapeHtmlAttr function, which is meant for escaping HTML attributes, not JSON data. This function can introduce double quotes in the JSON data, which can break the JSON syntax and cause errors.
• Option D: Use the script tag with the type attribute and the escapeJsQuote function to initialize the component with the JSON data. This option is not secure because it uses the escapeJsQuote function, which is meant for escaping JavaScript strings, not JSON data. This function can introduce backslashes in the JSON data, which can break the JSON syntax and cause errors.

The grunt watch command is used to track changes in the source files and recompiles CSS files automatically. This command is useful for frontend development as it allows the developer to see the changes in real time without manually running other commands. The grunt watch command can be run with or without parameters to specify the theme and locale. For example, to track changes for the Vendor/Orange theme and the en_US locale, the developer can use:

grunt watch --theme=Vendor/Orange --locale=en_US

The other two options are incorrect because they do not track changes in the source files. The grunt start command is used to register themes and clear caches before running other commands. The grunt less command is used to compile LESS files to CSS files for a specific theme and locale. References: Adobe Commerce Developer Documentation, Adobe Inc.

To find the default values for the buttons, the developer needs to look at the lib/web/css/source/lib/_buttons.less file. This file contains various variables, mixins, and styles for defining and customizing buttons. The developer can override these values in their custom theme by using the .lib-button() mixin or by creating their own mixins or classes. For example:

lib-button( @_button-selector, @_button-type, @_button-shape, @_button-color, @_button-background, @_button-border, @_button-text-transform, @_button-box-shadow, @_button-hover-color, @_button-hover-background, @_button-hover-border, @_button-hover-box-shadow );

The lib/web/less/source/lib/_buttons.less and lib/web/css/source/lib/_button.less files are not valid and do not exist. References: [Buttons], [Magento UI library]

To override the parent theme styles, the developer needs to change the web/css/source/_extend.less file in the child theme. This file is used to import and extend the parent theme styles without modifying the original files. The developer can use the @import directive to import the parent theme styles and then use the .lib-css() mixin to override the CSS properties. For example:

@import ‘source/_extend.less’; // Import parent theme styles .lib-css(color, red); // Override color property

The web/css/source/_extends.less and web/css/source/_theme.less files are not valid and will not work, as they do not follow the theme structure or the naming convention. References: [Theme inheritance], [Extend parent theme styles]

To move a block from one container to another, the developer needs to use the layout instruction with the element attribute specifying the name of the block and the destination attribute specifying the name of the container. The after attribute can be used to position the block relative to other blocks in the same container. The value “-” means that the block will be placed after all other blocks, i.e., as the last child. The value “last-child” is not valid for the after attribute and will not work. The element and destination attributes should use the names of the blocks and containers, not their aliases or classes. References: [Layout instructions], [Move an element]

To add a custom widget that extends the default Calendar Widget, the contents of the file would look like option B. This is because option B follows the correct syntax and structure for defining a jQuery widget in Magento. The code does the following steps:

• Defines a module with the name “Vendor_Module/js/calendar-widget” that depends on the “jquery/ui” and “Magento_Ui/js/lib/knockout/bindings/datepicker” modules.
• Returns a function that creates a new widget with the name “vendor.calendarWidget” that extends the base calendar widget class.
• Overrides the init function of the base calendar widget class to add custom logic or functionality to the widget.

Option A is not correct because it does not use the correct syntax for defining a jQuery widget. It uses a script tag instead of a define function, which is not valid for creating a module. It also uses an incorrect name for the widget, which should use a dot instead of a slash. Option C is not correct because it does not use the correct syntax for extending a widget. It uses an extend function instead of a widget function, which is not valid for creating a new widget. It also does not return anything from the module, which will cause an error. References: [jQuery widgets], [Calendar Widget]