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typescript function optional parameter


A TypeScript function is a group of statements which is used for performing a specific task. It provides the facility of code re-usability.

Every parameter is assumed to be required by the function, in TypeScript. In short, the number of parameters given to a function at function call has to match the number of parameters in the function definition. We can mark a parameter optional by appending a question mark to its name. Optional parameter should be the last parameter of the function.

Typescript function optional parameter syntax:

function function_name (param1:datatype, param2?:datatype)

Typescript function optional parameter example:

function dispDetails(fname:string,lname?:string) {  
   console.log("Fisrt Name",fname); 
 
   if(lname!=undefined)  
   console.log("Last Name",lname); 
}
dispDetails("Asmita");
dispDetails("Nidhi", "Gupta");

Try it:

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TypeScript Tutorial

TypeScript Overview.
Typescript vs Javascript.
Typescript let vs var.
TypeScript Hello World.
Typescript Data Types.
Typescript Variable Declaration.
TypeScript operators list.
TypeScript Arithmetic Operators.
TypeScript Comparison Operators.
TypeScript Bitwise Operators.
Typescript Logical Operators.
TypeScript Assignment Operators.
Typescript Conditional Operator.
Typescript String Operator.
Typescript typeof Operator.
TypeScript control statements.
TypeScript Switch Statement.
TypeScript for loop.
TypeScript for in loop.
TypeScript while loop.
TypeScript do while loop.
Typescript for loop break.
TypeScript for loop continue.
Typescript function.
Typescript returning function.
Typescript parameterized function.
Typescript function optional parameter.
Typescript rest parameters.
Typescript default parameters.
Typescript anonymous function.
Typescript function constructor.
Typescript Arrow/Lambda function.
Typescript function overloading.
TypeScript number object.
TypeScript string object.
TypeScript boolean object.
TypeScript date object.
TypeScript math object.
TypeScript array object.
TypeScript tuples.
TypeScript union type.
TypeScript interface.
TypeScript interface inheritance.
TypeScript interface multiple inheritance.
TypeScript class.
Typescript class inheritance.
Typescript class interface.
TypeScript abstract class.
TypeScript object.
TypeScript duck typing.
TypeScript NameSpace.
TypeScript Multi-file namespaces.
TypeScript module.
TypeScript ambient module.


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