Enums are a feature in TypeScript that help organize collections of related values. Accessing these values efficiently is crucial for clean, maintainable code. This guide provides a straightforward overview of different methods to access enum values in TypeScript, including bracket notation, dot notation, object lookup, and using Object.entries. Each method is explained with simple examples to enhance your coding techniques.

Examples of Accessing Enum Values in TypeScript

Using bracket notation

In this approach, we are using the bracket notation to access enum values in typescript. By using the enum name and the desired key within the square bracket we can access the enum value associated with that key.

Syntax:

const enumValue = EnumName['EnumKey'];

EnumName is the name of the enum.
EnumKey is the key of the enum whose value we want to access.

Example: The code below demonstrates how we can use the bracket notation to access enum values in typescript.

// Define Enum
enum GFG {
    Org = "GeeksForGeeks",
    Founder = "Sandip Jain",
    Est = "2009"
}

// Access Enum using bracket notation
let key: keyof typeof GFG = "Org";
let value = GFG[key];

console.log(value);

Output:

GeeksForGeeks

Using DOT notation

In this approach, we are using the dot notation to access enum values in typescript. It involves directly referencing the enum name followed by the enum member name (key) using a dot (.) syntax.

Syntax:

const enumValue = EnumName.EnumKey;

EnumName is the name of the enum.
EnumKey is the key of the enum whose value we want to access.

Example: The code below demonstrates how we can use the DOT notation to access enum values in typescript.

// Define Enum
enum GFG {
    Org = "GeeksForGeeks",
    Founder = "Sandip Jain",
    Est = "2009"
}

// Access Enum using DOT notation
let value1 = GFG.Org;
let value2 = GFG.Founder;
let value3 = GFG.Est;

console.log(value1);
console.log(value2);
console.log(value3);

Output:

"GeeksforGeeks"
"Sandip Jain"
"2009"

Using Object Lookup

Another approach involves using object lookup, which utilizes a mapping object to access enum values. This method offers flexibility and ease of use, especially in scenarios where dynamic key-value pairs are required.

Syntax:

const enumValue = EnumLookup[EnumKey];

EnumLookup: An object containing enum keys as properties and their corresponding values.
EnumKey: The key of the enum whose value we want to access.

Example: In this example we are following above explained approach.

// Define Enum
enum GFG {
    Org = "GeeksForGeeks",
    Founder = "Sandip Jain",
    Est = "2009"
}

// Create lookup object
const enumLookup = {
    Org: GFG.Org,
    Founder: GFG.Founder,
    Est: GFG.Est
};

// Access Enum using Object Lookup
let enumKey: keyof typeof GFG = "Org";
let value = enumLookup[enumKey];

console.log(value); 

Output:

GeeksForGeeks

Using Object.entries Method

This approach leverages Object.entries to convert the enum into an array of key-value pairs. Each pair is an array where the first element is the key (name of the enum member) and the second element is the value. This method is beneficial when you need to perform operations on both the keys and values of an enum.

Syntax:

for (let [key, value] of Object.entries(EnumName)) {
    console.log(`${key}: ${value}`);
}

• EnumName is the name of the enum.

Example:

Here’s how you can use Object.entries to access all keys and values of an enum in TypeScript:

enum StatusCode {
    SUCCESS = 200,
    NOT_FOUND = 404,
    INTERNAL_SERVER_ERROR = 500
}

for (let [key, value] of Object.entries(StatusCode)) {
    console.log(`${key}: ${value}`);
}

Output:

SUCCESS: 200
NOT_FOUND: 404
INTERNAL_SERVER_ERROR: 500