Example InptfieldPageTable hook module to remove "Add New" button on a condition

MyPageTableHooks.module

<?php

/**
 * Example Hooks to hack InputfieldPageTable to not render add buttons on a condition
 * This will remove "add new" buttons if there's more than 2 entries
 *
 * - First addHookBefore InputfieldPageTable::render to count the value (table rows)
 * - If value is greater than 1, we hadd another hook to InputfieldButton::render (used by page table for the buttons)
 *   and overwrite it with an empty string.
 * - Add another hook after page table render to remove the button hooks, to not remove any other buttons rendered
 *   after this page table
 *
 * @author  Soma <[email protected]>
 *
 *
 */

class MyPageTableHooks extends WireData implements Module {

    /**
     * getModuleInfo is a module required by all modules to tell ProcessWire about them
     *
     * @return array
     *
     */
    public static function getModuleInfo() {

        return array(
            'title' => 'My PageTable Hooks',
            'version' => 1,
            'summary' => 'An example module to hide "Add New" buttons on a condition.',
            'href' => 'http://www.processwire.com',
            'singular' => true,
            'autoload' => "process=ProcessPageEdit",
            'icon' => 'smile-o',
        );
    }

    /**
     * Initialize the module
     *
     * ProcessWire calls this when the module is loaded. For 'autoload' modules, this will be called
     * when ProcessWire's API is ready. As a result, this is a good place to attach hooks.
     *
     */
    public function init() {
        $this->buttonHook = null;
        $this->addHookBefore("InputfieldPageTable::render", $this, "renderPageTable");
        $this->addHookAfter("InputfieldPageTable::render", $this, "renderPageTableAfter");
    }

    public function renderPageTable(HookEvent $event){
         // get the table field
        $table = $event->object;

        // make sure this is our field
        if($table->name !== "mypagetable") return;

        // if there's 2+ rows add another hook to remove returned markup string
        // rendered by InputfieldButton::render
        if(count($table->attr("value")) > 1) {
            $this->buttonHook = $this->addHookAfter("InputfieldButton::render", null, function(HookEvent $event){
                // overwrite/remove button markup
                $event->return = '';
            });
        }
    }

    public function renderPageTableAfter(HookEvent $event){
        // if there's any button hooks set, remove the hook to not remove all buttons added to page
        // rendered after this page table
        if($this->buttonHook) $this->removeHook($this->buttonHook);
    }
}