Const
The Symbol.asyncIterator symbol is a builtin symbol that is used to access an
object's Symbol.asyncIterator
method. In order for an object to be async iterable,
it must have a Symbol.asyncIterator key.
See: Symbol.asyncIterator
The Symbol.hasInstance
well-known symbol is used to determine if a constructor
object recognizes an object as its instance. The instanceof operator's behavior
can be customized by this symbol.
See: Symbol.hasInstance
The Symbol.isConcatSpreadable
symbol (Symbol.isConcatSpreadable) can be defined as an
own or inherited property and its value is a boolean. It can control behavior for
arrays and array-like objects:
Whenever an object needs to be iterated (such as at the beginning of a for..of loop),
its Symbol.iterator
method is called with no arguments, and the returned iterator is used
to obtain the values to be iterated.
See: Symbol.iterator
This function is also used to identify if objects have the behavior of regular expressions. For example, the methods String.prototype.startsWith(), String.prototype.endsWith() and String.prototype.includes(), check if their first argument is a regular expression and will throw a TypeError if they are. Now, if the match symbol is set to false (or a Falsy value), it indicates that the object is not intended to be used as a regular expression object.
See: Symbol.match
The Symbol.matchAll
well-known symbol returns an iterator, that yields matches of the regular
expression against a string. This function is called by the String.prototype.matchAll() method.
See: Symbol.matchAll
The Symbol.replace
well-known symbol specifies the method that replaces matched substrings
of a string. This function is called by the String.prototype.replace() method.
For more information, RegExp.prototype[Symbol.replace]() and String.prototype.replace().
See: Symbol.replace
The Symbol.search
well-known symbol specifies the method that returns the index within a
string that matches the regular expression. This function is called by the
String.prototype.search()
method.
For more information, see RegExp.prototype[@@search]() and String.prototype.search().
See: Symbol.species
The well-known symbol Symbol.species
specifies a function-valued property that the constructor
function uses to create derived objects.
See: Symbol.species
The Symbol.split
well-known symbol specifies the method that splits a string at the indices
that match a regular expression. This function is called by the String.prototype.split() method.
For more information, see RegExp.prototype[@@split]() and String.prototype.split(). See: Symbol.split
With the help of the Symbol.toPrimitive
property (used as a function value), an object can be
converted to a primitive value. The function is called with a string argument hint, which
specifies the preferred type of the result primitive value. The hint argument can be one of
"number", "string", and "default".
See: Symbol.toPrimitive
The Symbol.toStringTag
well-known symbol is a string valued property that is used in the
creation of the default string description of an object. It is accessed internally by the
Object.prototype.toString()
method.
See: Symbol.toStringTag
The Symbol.unscopables
well-known symbol is used to specify an object value of whose own
and inherited property names are excluded from the with environment bindings of the associated
object.
See: Symbol.unscopables
Identifies the Symbol static properties which are symbols themselves as a constant enum to aid in minification when fetching them from the global symbol implementation.
See: Well Known Symbols