JavaScript Symbol.species Property

The Symbol.species property specifies a function-valued property that the constructor function uses to create derived objects. With this, we can create a derived object.

Syntax:

[Symbol.species]

Attribute: The species accessor property can be used to allow subclasses to override the default constructor for objects.

Example 1:

Javascript

class geek extends Array {
    static get [Symbol.species]() {
    return Array;
    }
}

const a = new geek(1, 2, 3, 4);

const mapped = a.map((x) => 2);

console.log(mapped instanceof geek);

console.log(mapped instanceof geek);

Output:

false
false

Example 2:

Javascript

class geek extends Array {
static get [Symbol.species]() {
return Array;
}
}
let a = new geek(1, 2, 3, 5, 7, 8);
let mapped = a.map((x) => x);

console.log(mapped instanceof geek);
console.log(mapped instanceof Array);

Output:

false
true

We have a complete list of Javascript symbols, to check those please go through the Javascript Symbol Complete Reference article.

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