The JavaScript exception "setter functions must have one argument" occurs when a setter is declared and the parameter list is not consisted of exactly one formal parameter.

The JavaScript exception "unlabeled break must be inside loop or switch" occurs when a break statement is not inside a loop or a switch statement.

The shape-rendering attribute provides hints to the renderer about what tradeoffs to make when rendering shapes like paths, circles, or rectangles.

The JavaScript exception "missing } after property list" occurs when there is a mistake in the object initializer syntax somewhere. Might be in fact a missing curly bracket, but could also be a missing comma.

The division operator `/`.

The get() method of WeakMap instances returns the value corresponding to the key in this WeakMap, or undefined if there is none. Object values are returned as the same reference that was originally stored, not as a copy, so mutations to the returned object will be reflected anywhere that reference is held, including inside the WeakMap.

The Reflect.getOwnPropertyDescriptor() static method is like Object.getOwnPropertyDescriptor(). It returns a property descriptor of the given property if it exists on the object, undefined otherwise.

The has() method of WeakMap instances returns a boolean indicating whether an entry with the specified key exists in this WeakMap or not.

The Object.defineProperty() static method defines a new property directly on an object, or modifies an existing property on an object, and returns the object.

The getOrInsert() method of WeakMap instances returns the value corresponding to the specified key in this WeakMap. If the key is not present, it inserts a new entry with the key and a given default value, and returns the inserted value.