• Code quality principle
• States that every piece of logic should have one representation.
• In JavaScript usage, functions should do on thing. Combine multiple function to achieve usage.
• Allows you to modify on function without affecting the program at large.
• I don't go crazy over this stuff, but it's always good to have in the back of your head when programming.
• Antithesis is WET, or "we enjoy typing", "write everything twice"

• Reorganizing your code to reduce duplication, increase readability, or adhere to the DRY principle.
• Should not change functionality (may change performance).
• Normally happens once you achieve MVP functionality.
• Can happen while you're still in development.
• Essential if you want to come back and understand your code.

• First argument is a String or RegExp to match.
• Second argument is a string to insert in its place.
• Returns the full, modified string.
• Does not modify the original string.
• Only finds and replaces the first instance of the argument. (Except when using special RegExp)

"this is a dog".replace("dog","cat");// > "this is a cat""this is a cat".replace(/cat/, "unicorn");// > this is a unicorn"i'm a dog, i'm a dog, i'm a dog".replace(/dog/, "bird");// > i'm a bird, i'm a dog, i'm a dog"i'm a bird, i'm a bird, i'm a bird".replace(/bird/g, "dog");// > i'm a dog, i'm a dog, i'm a dog

• Certain JavaScript functions lend themselves to chaining.
• Only works when the next function can be called on the returned object of the first.
• jQuery functions are usually always able to be chained.
• This can make code difficult to read.
• Best practice to put each function on a new line.

 "I have a dog, cat, and mouse".replace("dog","stick").                               replace("cat","rock").                               replace("mouse","dirt");//I have a stick, rock, and dirt. :-(

 var template = '<label>{{label}}<input      placeholder="{{placeholder}}"></input>   </label>';