JavaScriptConfig: A utility class to add in configuration information for JS files in the head tag.

JavaScriptConfig.php

<?php
/**
 * JavaScriptConfig
 * A utility class to add in configuration information for JS files in the head
 * section, directly from PHP and json_encode with Requirements.
 * Used with SilverStripe 2.4+
 * @author @willmorgan
 */
class JavaScriptConfig {

	protected static
		$config_name = 'JS_CONFIG',
		$configs = array(),
		$has_written = false,
		$written_configs = array();

	static function add($paramName, $paramVal) {
		self::$configs[$paramName] = $paramVal;
		if(self::$has_written) {
			self::insert();
		}
	}

	static function insert() {
		if(!self::$has_written) {
			if(empty(self::$configs)) {
				$json = '{}';
			}
			else {
				$json = Convert::array2json(self::$configs);
			}

			$html = '<script>window.'.self::$config_name.' = ' . $json . ';</script>';
			self::$has_written = true;
		}
		else {
			$js = '';
			foreach(self::$configs as $paramName => $paramVal) {
				$js .= self::$config_name . '[\''.$paramName.'\'] = ' . json_encode($paramVal) . ";\n";
			}
			$html = '<script>' . $js .'</script>';
		}
		self::$written_configs = array_merge(self::$written_configs, self::$configs);
		self::$configs = array();
		Requirements::insertHeadTags($html);
	}

}