I love Ruby's ||= mechanism. If a variable doesn't exist or is nil, then create it and set it equal to something:

amount # is nil

amount ||= 0 # is 0

amount ||= 5 # is 0

I need to do something similar in JavaScript now. What's the convention or proper way to do this? I know ||= is not valid syntax. 2 obvious ways to handle it are:

window.myLib = window.myLib || {};



// or



if (!window.myLib)

  window.myLib = {};