Private elements are counterparts of the regular class elements which are public, including class fields, class methods, etc. Private elements get created by using a hash # prefix and cannot be legally referenced outside of the class. The privacy encapsulation of these class elements is enforced by JavaScript itself. The only way to access a private element is via dot notation, and you can only do so within the class that defines the private element.

The JavaScript strict mode-only exception "0-prefixed octal literals are deprecated; use the "0o" prefix instead" occurs when deprecated octal literals (0 followed by digits) are used.

The fill attribute has two different meanings. For shapes and text it's a presentation attribute that defines the color (or any SVG paint servers like gradients or patterns) used to paint the element; for animation it defines the final state of the animation.

The get syntax binds an object property to a function that will be called when that property is looked up. It can also be used in classes.

The do...while statement creates a loop that executes a specified statement as long as the test condition evaluates to true. The condition is evaluated after executing the statement, resulting in the specified statement executing at least once.

The Uint8Array typed array represents an array of 8-bit unsigned integers. The contents are initialized to 0 unless initialization data is explicitly provided. Once established, you can reference elements in the array using the object's methods, or using standard array index syntax (that is, using bracket notation).

The toPrecision() method of Number values returns a string representing this number to the specified number of significant digits.

The delete() method of WeakSet instances removes the specified value from this set, if it is in the set.

The has() method of WeakSet instances returns a boolean indicating whether the specified value exists in this WeakSet or not.

The toLocaleString() method of Number values returns a string with a language-sensitive representation of this number. In implementations with Intl.NumberFormat API support, this method delegates to Intl.NumberFormat.