API design guidelines

jQuery Core project guidelines:

• Provide a set of APIs that work consistently across supported browsers.
• Document exceptions where consistency is impractical or impossible.
• Work with browser makers to make the web platform behave consistently.

jQuery API guidelines:

• Avoid Boolean traps. - In particular, there should never be more than one Boolean value in an API signature.
• Avoid global state. - APIs such as jQuery.ajaxSetup() affect behavior globally, making it difficult for a plugin author to depend on default values.
• Undocumented inputs result in unpredictable output. - The API may throw an error inside jQuery, do nothing, or have some unpredictable behavior. This may change without warning across versions, even minor patches.
• Use .api(name) for getters and .api(name, value) for setters.
• A getter on an empty jQuery collection returns undefined.