What does symbol mean in js

Symbol is a unique identifier in JavaScript. It is used as an object attribute name to prevent naming conflicts. It is unique, immutable and private. It can be created and assigned through Symbol() and is only strictly equal to itself. Compare.

Symbol in JavaScript

Symbol is a primitive data type in JavaScript that represents a unique identifier . It was first introduced in the ES6 (ECMAScript 2015) release.

Usage:

Symbol is mainly used to create unique property names to avoid naming conflicts and enhance code readability.

Characteristics:

• Uniqueness: Every Symbol is different, even if they have the same value.
• Immutability: Once a Symbol is created, its value cannot be modified.
• Privateness: Unlike regular properties, Symbol properties will not appear in regular iterations, such as for...in loops.
• Assignment: Symbol can be assigned to variables like other primitive data types.

Create Symbol:

Use Symbol() function to create Symbol:

<code class="js">const mySymbol = Symbol();</code>

Compare Symbol:

Since Symbols are unique, they can only be strictly equal to themselves (===) Comparison:

<code class="js">console.log(mySymbol === mySymbol); // true
console.log(mySymbol === Symbol()); // false</code>

As Property name:

Symbol can be used as the name of an object's property, thus freeing it from naming conflicts:

<code class="js">const person = {
  [Symbol("name")]: "John Doe",
  age: 30
};

console.log(person[Symbol("name")]); // "John Doe"</code>

Other usage:

Symbol has other uses, including:

• Create custom iterator interfaces
• Identify private methods or properties
• Enhance test readability and maintainability

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