最初の一回だけ実行される関数を生成する関数 - Qiitavar toExecutableOnce = function(f){ var called = false, result = undefined; return function(){ if(!called){ result = f.apply(this, arguments); called = true; } return result; }; }; var greeting = toExecutableOnce(function(){ console.log("hello"); return "world"; }); console.log(greeting());// hello world console.log(greeting());// world
