The **setter-method** library provides a tiny utility for adding chainable getter/setter functions to any JavaScript object, eliminating the need to write repetitive boilerplate code. By calling `addSetter(object, key, defaultValue)` you get a method that returns the stored value when called with no arguments and sets a new value (while returning the object for chaining) when called with an argument—ideal for front‑end developers building configurable components or libraries.