A modifier overrides flag settings in a specific part of a regular expression. It can be used to enable or disable flags that change the meanings of certain regex syntax elements. These flags are i, m, and s.

The JavaScript exception "can't access lexical declaration 'X' before initialization" occurs when a lexical variable was accessed before it was initialized. This happens within any scope (global, module, function, or block) when let or const variables are accessed before the place where they are declared is executed.

The concat() method of Array instances is used to merge two or more arrays. This method does not change the existing arrays, but instead returns a new array.

Learn about running workflows and jobs simultaneously.

The Symbol.asyncIterator static data property represents the well-known symbol Symbol.asyncIterator. The async iterable protocol looks up this symbol for the method that returns the async iterator for an object. In order for an object to be async iterable, it must have a [Symbol.asyncIterator] key.

Immutable slice iterator

The Symbol.unscopables static data property represents the well-known symbol Symbol.unscopables. The with statement looks up this symbol on the scope object for a property containing a collection of properties that should not become bindings within the with environment.

You can host your own runners and customize the environment used to run jobs in your GitHub Actions workflows.

The split() method of String values takes a pattern and divides this string into an ordered list of substrings by searching for the pattern, puts these substrings into an array, and returns the array.

The matchAll() method of String values returns an iterator of all results matching this string against a regular expression, including capturing groups.