How to execute TypeScript file using command line?

TypeScript is a statically-typed superset of JavaScript that adds optional type annotations and compiles to plain JavaScript. It helps catch errors during development. To execute a TypeScript file from the command line, compile it using tsc filename.ts, then run the output JavaScript file with node.

Syntax:

To check node is installed, run command if not you have to installed it first:

node -v

Now to install typescript, use:

npm install -g typescript

After installing typescript, create a .ts file, for example, greet.ts as given below:

Example:javascript

let greet: string = "Greetings"; 
let geeks: string = "GeeksforGeeks"; 
console.log(greet + " from " + geeks); 
// save the file as hello.ts 

Output:

Greetings from GeeksforGeeks

Procedure 1: This typescript file greet.ts will create a javascript file at runtime with the same name. To run any typescript file there are a few ways:

Syntax:

Step 1: First, run the typescript file with the following command. This will create a javascript file from typescript automatically with the same name.

tsc helloWorld.ts

Step 2:Now run the javascript file, the greet.ts file will get executed:

node helloWorld.js

Procedure 2: You can merge both the commands by using a pole | and && like below :

Syntax:

In Windows:

tsc greet.ts | node greet.js

In Linux or MacOS:

tsc helloWorld.ts && node helloWorld.js

Procedure 3: You can also install ts-node along with typescript using the following command:

Syntax:

To install:

npm install -g ts-node

To run:

ts-node helloWorld.ts

Output: Using any of the three ways, the output will remain the same.

Greetings from GeeksforGeeks