The Object.seal() static method seals an object. Sealing an object prevents extensions and makes existing properties non-configurable. A sealed object has a fixed set of properties: new properties cannot be added, existing properties cannot be removed, their enumerability and configurability cannot be changed, and its prototype cannot be re-assigned. Values of existing properties can still be changed as long as they are writable. seal() returns the same object that was passed in.

The Intl.getCanonicalLocales() static method returns an array containing the canonical locale names. Duplicates will be omitted and elements will be validated as structurally valid language tags.

The trimStart() method of String values removes whitespace from the beginning of this string and returns a new string, without modifying the original string. trimLeft() is an alias of this method.

The padEnd() method of String values pads this string with a given string (repeated, if needed) so that the resulting string reaches a given length. The padding is applied from the end of this string.

The toString() method of Boolean values returns a string representing the specified boolean value.

The Symbol.for() static method searches for existing symbols in a runtime-wide symbol registry with the given key and returns it if found. Otherwise a new symbol gets created in the global symbol registry with this key.

The toString() method of Symbol values returns a string representing this symbol value.

The Promise.reject() static method returns a Promise object that is rejected with a given reason.

The finally() method of Promise instances schedules a function to be called when the promise is settled (either fulfilled or rejected). It immediately returns an equivalent Promise object, allowing you to chain calls to other promise methods.

The Symbol.split static data property represents the well-known symbol @@split. The String.prototype.split() method looks up this symbol on its first argument for the method that splits a string at the indices that match the current object.