What's the syntax for CKEDITOR.replaceAll custom assertion functions?

Question

I would like to selectively avoid replacing textareas with CKEDITOR.replaceAll. I cannot simply use replace instead. I must use custom assertion functions mentioned in the documentation.

http://docs.ckeditor.com/#!/api/CKEDITOR-method-replaceAll

// Selectively replace <textarea> elements, based on custom assertions.
CKEDITOR.replaceAll( function( textarea, config ) {
    // An assertion function that needs to be evaluated for the <textarea>
    // to be replaced. It must explicitely return "false" to ignore a
    // specific <textarea>.
    // You can also customize the editor instance by having the function
    // modify the "config" parameter.
} );

But there is no assert in javascript. What's the syntax for the assertions?

Answer 1

The use of "assertion function" in the CKEDITOR documentation is misleading. There is no assert in javascript. Just use a conditional and return false to ignore a specific textarea.

Example:

CKEDITOR.replaceAll(function (textarea, config) {
    if (textarea.classList.contains("ignore_me")) {
        return false;
    };
    <...>
});