How to ruin your code (story) ? β
π As i said earlier , when i was beginning with programming i was so foolish to not to follow coding principles like DRY (don't repeat yourself).
π One definition was assigned to me , which was "write a program where have to do addition of 2 numbers 3 times"
π The code i wrote earlier :
var num1 = propmt("Enter no : ");
var num2 = propmt("Enter no : ");
var res = 0;
res = num1+num2;
console.log(res);
var num3 = propmt("Enter no : ");
var num4 = propmt("Enter no : ");
res = num3+num4;
console.log(res);
var num5 = propmt("Enter no : ");
var num6 = propmt("Enter no : ");
res = num5+num6;
console.log(res);
π This does make sense as a beginner , but when you think in terms of performance optimization , speed and quality of code - this doesn't make any sense.
π After that i was introduced to concept known as Function
Functions :
π According to internet , Functions are one of the fundamental building blocks in JavaScript. A function in JavaScript is similar to a procedureβa set of statements that performs a task or calculates a value, but for a procedure to qualify as a function, it should take some input and return an output where there is some obvious relationship between the input and the output.
π To put it more simply and making it clear we'll go to our previous definition of 3 times of addition. so what we can say is that a perfect function is a mechanism to reduce that 3 times repeating code into simple block of code which can work for 3 or 30 or even 300 times depending on logic inside it. function simply means act of writing a reusable code.
Syntax of function
π Making a function can be defined in three steps
Function Definition : telling your compiler that there's a function in our program.
Function Body : Block of code to be executed when function gets called.
Function Call : Calling a function simply tells your compiler that execute the code written in function body in respective context.
How does that looks like?
π functions takes parameters as input process it in function body and returns
output.
π Parameters simply means input values which function is expecting for further process.
π Arguments means actual value passed to the respective parameter
π Example
// sum is name of function
// num1 and num2 are params
function sum(num1,num2){
// function body
var res = num1+num2;
return res;
}
//2 and 5 are actual arguments
// function call ();
sum(2,5);
// outputs 7
Rules
π Name of function should be unique
π Function should be defined somewhere in program before calling it
π Function may or may not take parameters
π Function may or may not return value
π Function can take 0 to n number of parameters depending on need
π Function can be called multiple times during execution
π Example of function without params and return statements
function greet(){
console.log("Good Morning");
}
// can be called n number of times
greet();
greet();
greet();
Let's make it more optimized π
π We'll take our addition program and turn it into a super optimized code
π in app.js
function sum()
{
var num1 = +prompt("Enter no : ");
var num2 = +prompt("Enter no : ");
return num1+num2;
}
//calls function 3 times
for(var i=0;i<3;i++) {
sum();
}
Let me know in comment section if you have any doubt or feedback. it's always worth to give time to thriving developer community :)
Keep Coding β€
Top comments (8)
nice feature image
Thank you so much buddy, glad you liked it ...
Hello, this statement in sum function
var res = num1+num2;
You forgot to return res
So sum(2,5) wont return anything
Corrected* ! Thanks ahmed :)
Nice one. What after this?
Object oriented JavaScript, which will help you guys in frontend interviews
Enjoying your series - nice work.
Hey @realtoughcandy .io that's so nice of youπ this is going to be the best thing ever happened during the series.
The best part is when you see someone commenting on your blog who's absolute inspiration for you and you grew up watching their videos on YouTube π₯
Thank you so much π