functions in Javascript

functions in Javascript helps to develope reuseable code
Meaning - Instead of writing the same code again and again we can use function to reuse the code as number of times required

Syntax:
function calcAdd(num1,num2){
let total = num1+num2;
return total;
}

• function is the keyword referring that we are writing a function
• calcAdd is the name given to the function
• num1 and num2 are the parameters passed inside the function to execute addition operation
• return is the keyword used to return the output once the function is called

Execution:
let output = caclAdd(20,35);
console.log(output)

• Once the function is called 20 and 35 are the arguments that takes the places of parameters num1 and num2
• perform addition operation and store the value 55 in the variable total
• As we have returned the value it will now be stored in the output variable

Points to remember:

1. funtion can be declared with any number of parameters.
2. unlike Java, Javascript executes even if the arguments are not passed or passed with incorrect number of arguments.
3. return keyword should be used only at the end of the function before the closing parenthesis
4. If return keyword were to be used in the middle of the function then the remaining code will simply be skipped
5. If a variable is declared inside a function it can't be accessed outside the function for example in the syntax a variable total has been declared inside the function, it cannot be accessed outside if the total variable to be put in a console log outside the function output will be "ReferenceError: total is not defined" this makes return keyword handy to get the value from total variable to outerscope

TBD (number of Ways to declare a function and the purpose of doing so)

REFERRED IN MDN