There are two ways to discover the hook name of a specific component. With the hook name, you can locate its base template file.
First, if you already know the filename of the template, you can infer the hook name from that.
The typical pattern for naming template files is {hook}--{optional context}.html.twig
You can ignore the .html.twig suffix. Which results in {hook}--{optional context}
If the file name doesn't contain a --{optional context} part, then after removing .html.twig you're left with the hook name.
Examples:
node.html.twig: hook name is nodenode--blog_post.html.twig: hook name is nodefield--node--title--page.html.twig: hook name is field
Preprocess functions follow a specific naming convention:
THEMENAME_preprocess_HOOK() or HOOK_preprocess_HOOK()
HOOK is roughly the name of the template file for which you want to preprocess data.
The complete list of preprocess functions called for a template file is below, listed in the order they are called (if they exist):
template_preprocess(&$variables, $hook): Creates a default set of variables for all theme hooks with template implementations. Provided by Drupal Core.template_preprocess_HOOK(&$variables): Should be implemented by the module that registers the theme hook, to set up default variables.MODULE_preprocess(&$variables, $hook):hook_preprocess()is invoked on all implementing modules.MODULE_preprocess_HOOK(&$variables):hook_preprocess_HOOK()is invoked on all implementing modules, so that modules that didn't define the theme hook can alter the variables.ENGINE_engine_preprocess(&$variables, $hook): Allows the theme engine to set necessary variables for all theme hooks with template implementations.ENGINE_engine_preprocess_HOOK(&$variables): Allows the theme engine to set necessary variables for the particular theme hook.THEME_preprocess(&$variables, $hook): Allows the theme to set necessary variables for all theme hooks with template implementations.THEME_preprocess_HOOK(&$variables): Allows the theme to set necessary variables specific to the particular theme hook.
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