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Same like javascript, TypeScript have typeof Operator to check datatype of variable. using typeof we are able to check any variable type and compare with our own condition.

Let start today tutorial How to check type of variable in typescript?

TypeScript provide typeguard and typeof one of them. we will all of them but in this tutorial we will focus on typeof.

typeof example

let str: string = "01234";
console.log(typeof str);

if(typeof str == 'string'){
  console.log("str is string");
}

Output

Typescript, typeof, example

Handle multiple probabilities of data type

let str: string | number;

str = 123;

console.log(typeof str);

if(typeof str == 'number'){
  console.log("str is number");
}

Output

Typescript, typeof, example