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JavaScript Symbol Reference

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JavaScript symbol is a data type of primitive data type. The Symbol() function returns the symbol value type. The value returned from Symbol() is unique.

Syntax:

[Symbol.property](string)

Example: JavaScript code to show the working of this function. 

Javascript




// Creating some arrays
const Array1 = [1, 2, 3];
const Array2 = [4, 5, 6];
 
// Calling concat() function
let Array3 = Array1.concat(Array2);
 
// Printing the concatenated array
console.log(Array3);
 
// Calling Symbol.isConcatSpreadable symbol
Array2[Symbol.isConcatSpreadable] = false;
Array3 = Array1.concat(Array2);
 
// Printing the concatenated array
// after calling of Symbol.isConcatSpreadable symbol
console.log(Array3);


Output:

 Array [1, 2, 3, 4, 5, 6]
Array [1, 2, 3, Array [4, 5, 6]]

The complete list of JavaScript Symbol is listed below:

JavaScript Symbol Constructor: In JavaScript, a constructor gets called when an object is created.

Constructor Description Example
Symbol() Used to create a symbol object
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JavaScript Symbol Properties: A JavaScript property is a member of an object that associates a key with a value.

  • Static Property: A static property is a property that has the same value for the entire class.

Properties

Description 

Example 

asyncIterator It sets an object as async iterable
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hasInstance Determine if a given constructor object recognizes the object as its instance.
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isConcatSpreadable Given object should be flattened to its array elements while using the Array.prototype.concat() method.
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iterator It makes an element easier to use in for..of loop
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match It identifies matching of a Regular Expression to a string
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matchAll It returns Regular Expression that matches the String
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replace Replace the matched substring of a string.
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search Returns the index within a string that matches the regular expression. 
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species It is used to create a derived object from a function-valued property 
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split Specify the method that splits a string at the indices that match a regular expression.
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toStringTag Creation of the default string description of an object.
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unscopables Specify an object value of whose own and inherited property names are excluded from the environment bindings.
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  • Instance Properties: An instance property is a property that has a new copy for every new instance of the class.

 Properties

Description

Example

constructor Return the string constructor function for the object.
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description Return the optional description of the specified symbol objects.
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JavaScript Symbol Methods: JavaScript methods are actions that can be performed on objects. There are two types of Symbol methods in JavaScript.

  • Static Method: If the method is called using the symbol class itself then it is called a static method.

 Methods 

Description

Example

for() The Symbol.for() is used to search for the given symbol
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keyFor() This key is retrieved from the global symbol registry.
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  • Instance Method: If the method is called on an instance of a Symbol then it is called an instance method.
Methods Description Example
toString() convert the specified symbol object into the string.
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valueOf() Return the primitive value of a given symbol object.
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@@toPrimitive() Convert a given symbol object to a primitive value.
Try



Last Updated : 01 Mar, 2024
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