Example Typescript project

CLI Calculator Tutorial - Typescript Project for Beginners

Tutorial

import{question}from"readline-sync";typeOperator='+'|'-'|'*'|'/';functionmain():void{constfirstStr: string=question("Enter first number:\n");constoperator: string=question("Enter Operator:\n");constsecondStr: string=question("Enter Second number:\n");constvalidInput: boolean=isNumber(firstStr)&&isOperator(operator)&&isNumber(secondStr);console.log(validInput);if(validInput){console.log('is valid');constfirstNum: number=parseInt(firstStr);constsecondNum: number=parseInt(secondStr);constresult=calculate(firstNum,operatorasOperator,secondNum);console.log(result);}else{console.log('\ninvalid input\n');main();}}functionisNumber(str: string): boolean{constmaybeNum=parseInt(str);constisNum: boolean=Boolean(maybeNum);returnisNum;}functionisOperator(operator: string): boolean{switch(operator){case'+':
case'-':
case'-':
case'-':
returntrue;default:
returnfalse;}}functioncalculate(firstNum:number,operator:Operator,secondNum:number){switch(operator){case'+':
returnfirstNum+secondNum;case'-':
returnfirstNum-secondNum;case'*':
returnfirstNum*secondNum;case'/':
returnfirstNum/secondNum;}}main();

Use the below commands to Convert and run the code

Below code is used to convert the TypeScript to JavaScript

tsc index.ts

index.ts is used because the above TypeScript code is written in an index.ts file

To Run the code

node index.js

Sample output is shown below