Unsure whether it’s “log in” or “login”, “set up” or “setup”, and so on? Have a cheatsheet.
“check out” vs. “checkout”
In a sentence: “I check out on the checkout page.”
“Check out” is what you do.
A “checkout” (or “check-out”) is a thing: the act of checking out. It’s also used in phrases like “a checkout page”.
In a phrase like “a checkout page”, the word “checkout” acts as a noun adjunct.
“log in” vs. “login”
In a sentence: “I log in on the login page, with my user login and password.”
“Log in” is what you do.
A “login” (or “log-in”) is a thing: the act of logging in, or the credentials you use to do so. It’s also used in phrases like “a login page”.
“log out” vs. “logout”
In a sentence: “I will log out on the logout page.”
“Log out” is what you do.
A “logout” (or “log-out”) is a thing: the act of logging out. It’s also used in phrases like “a logout page”.
“set up” vs. “setup”
In a sentence: “I will set up my account on the setup page.”
“Set up” is what you do.
A “setup” is a thing: the act of setting something up. It’s also used in phrases like “a setup page”.
I believe “set-up” with a hyphen is not commonly used in an IT sense. (Corroboration.)
“sign up” vs. “signup”
In a sentence: “I will sign up on the signup page.”
“Sign up” is what you do.
A “signup” (or “sign-up”) is a thing: the act of signing up. It’s also used in phrases like “a signup page”.
Why should you care?
Language is determined by use and ever in flux – there’s no right or wrong as such, but the above is what I believe most dictionaries and nitpickers would propose.
Not making these distinctions looks just as bad as any other typo to those of us who are sensitive to the difference, and it is unnecessarily misleading – I would expect a
setupController method to return the controller for setting things up, not to perform the action of setting up a controller.
I’ve seen a lot of people get it “wrong” – in my team’s code review as well as in major public projects like Ember.js.
By making these distinctions, those who notice will be happier, and those who don’t won’t care either way.