The isWellFormed() method of strings returns a boolean indicating if the string contains any Unicode lone surrogates. The toWellFormed() method returns a new string where all lone surrogates are replaced by the Unicode replacement character.

The at() method of strings returns the character (one UTF-16 code unit) at an index, including negative indices for getting the character relative to the end of the string. Also known as the relative indexing method.

The replaceAll() method of strings returns a new string where all matches of a pattern (a string or regular expression) have been substituted with a replacement string.

The matchAll() method of strings matches a string against a regular expression and returns an iterator of all results, including capturing groups.

The trimStart() and trimEnd() methods of strings return a new string with whitespace removed from the beginning or end of the string.

The padStart() and padEnd() methods of strings return a string lengthened to a minimum number of characters by adding characters to the start or end of the string.

The normalize() method of strings returns a Unicode normal form of a string as a new string. More than one code point sequence can represent the same characters. You can use the normalize() method to find canonically or compatibly equivalent strings.

The codePointAt() method returns the numeric value of the UTF-16 code point at an index of the string. The fromCodePoint() method returns a string created from one or more code points.

The includes() method of strings returns whether a search string appears within the string.

The String.raw() static method interpolates template literal substitutions, but ignores escape sequences. It is the tag function for template literals.

The repeat() method of strings returns the original string repeated a number of times.

The startsWith() and endsWith() methods of strings returns whether a search string appears at the beginning or end of the provided string.