The WeakSet() constructor creates WeakSet objects.

The JavaScript exception "invalid date" occurs when an invalid date is attempted to be converted to an ISO date string.

A non-capturing group groups a subpattern, allowing you to apply a quantifier to the entire group or use disjunctions within it. It acts like the grouping operator in JavaScript expressions, and unlike capturing groups, it does not memorize the matched text, allowing for better performance and avoiding confusion when the pattern also contains useful capturing groups.

The pointsAtX attribute represents the x location in the coordinate system established by attribute primitiveUnits on the <filter> element of the point at which the light source is pointing.

The JavaScript error "unterminated string literal" occurs when there is an unterminated string literal somewhere. String literals must be enclosed by single (') or double (") quotes.

The preserveAspectRatio attribute indicates how an element with a viewBox providing a given aspect ratio must fit into a viewport with a different aspect ratio.

The JavaScript exception "function statement requires a name" occurs when there is a function statement in the code that requires a name.

The stroke-dasharray attribute is a presentation attribute defining the pattern of dashes and gaps used to paint the outline of the shape;

The JavaScript exception "invalid assignment left-hand side" occurs when there was an unexpected assignment somewhere. It may be triggered when a single = sign was used instead of == or ===.

The refY attribute defines the y coordinate of an element's reference point.