How can I replace content in the WP Admin area before an admin page is rendered?

Question

Wordpress has a filter called the_content where one can, for example, change all occurrences of the word "foo" to "bar" in the callback function:

add_filter('the_content','callback');
function callback($content){
    $content = str_ireplace("foo","bar",$content);
    return $content;
}

My question is how can I do the same thing in the admin area?

We are rebranding a plugin, and if you've tackled that before, you know it gets a bit more involved than doing a simple "search and replace."

What I'd like to do in the meantime is find and replace "OldPluginBranding" with "NewPluginBranding" whereever it occurs in the wp-admin area. the_content filter doesn't seem to work in that area, however.

Answer 1

There's no filter for filtering all of the HTML output in the admin. The closest thing is the gettext filter:

function wpse_275812_filter_text( $translated_text, $text, $domain ) {
    $translate_text = str_ireplace( 'foo', 'bar', $translated_text );

    return $translated_text;
}
add_filter( 'gettext', 'wpse_275812_filter_text' );

This filters any text output by the internationalization functions (__(), _e(), etc.). So it will only work if the plugin you're trying to filter uses these functions to output its text.

If it doesn't, there's nothing you can really do.