小键人14211450的《箭头函数》成绩 - 打字成绩 - 在线打字练习（dazi.91xjr.com）

const double1 = function(number){ return number * 2; } const double2 = (number) => { return number * 2; } const double3 = (number) => number * 2; const double4 = number => number * 2; cons...