--- /dev/null
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+ value: true
+});
+exports.default = once;
+function once(fn) {
+ return function () {
+ if (fn === null) return;
+ var callFn = fn;
+ fn = null;
+ callFn.apply(this, arguments);
+ };
+}
+module.exports = exports["default"];
\ No newline at end of file