TypeScript Union

Union in typescript are used to define the data type of variable when variable store more than one data type values.

let data: (string | number | boolean);

data = 10; //ok
console.log("data : ",data);

data = true; //ok
console.log("data : ",data);

data = "Code"; //ok
console.log("data : ",data);

data :  10
data :  true
data :  Code

Union as function parameter

We can use union to define variable of function parameter list.

function message(data:(string|number)){
  console.log("data : ",data);
}
message("Hello Programmer");
message(999);

data :  Hello Programmer
data :  999