Function assert

src/piper.js:133–135

(check, msg)

					);
				function runWithFS() {
					function assert(check, msg) {
						if (!check) throw msg + new Error().stack;
					}
					Module['FS_createPath']('/', 'espeak-ng-data', true, true);
					Module['FS_createPath']('/espeak-ng-data', 'lang', true, true);
					Module['FS_createPath']('/espeak-ng-data/lang', 'aav', true, true);