CppToJs

Some informations-

• numbers in js is 64 bit
• each character in a string in js is 16 bit
• maximun float number we can use in the range of 10^15
• naming convection of function is - newFunctionName
• NaN == NaN -> this returns false
• null == undefined -> this returns true

To decleare a variable you can use var or let. let is more standard. lifetime of var is equivalent to the variable of C++. var will be global wherever you declear.

  	let v1 = 1, v2 = 2;

function

uning function keyword

	const name = function(par1, par2){
		// code
		// return
	};
	name(par1, par2); // function call

We can create function inside a function which was not possible in C++

	const name1 = function(par){
		// code
		const name2 = function(par1, par2){
			//code
			// return 
		};
		name2(par1, par2); // function call
		// code
		// return
	};
	name1(par); // function call

if we don’t decleare funtion as contant then we can put different function in the same name

	let name = function(){
		// function 1
	};
	
	name = function(){
		// function 2
	};

We can also declear function like C++. It is easier and we don’t neet to pur ; at the end.

	function funcName(){
		// code
		// return
	}

Arrow fuction. Here we can relate with the first type, we replace function with => and put it after the parameter.

	const name = (par1, par2) => {
		// code
		// return
	};

Note: If we put extra parameter or less parameter if the function

1) ignores the extra arguments
	const name = function(par){
		// here we will get par1, and others have no effect 
	}
	name(par1, par2, par3);
	
2) missing parameters will be undefined
	const name(par1, par2){
		// here par2 = undefined
	}
	name(par1);
	
	but if we do - const name(par1, par2=2){ }. then par2 = 2, if it is not provided/

Closure.

	function name(par1){ // first function
		let x = par1;
		// code
		return (par2) => { par1 * par2; } // second function
	}
	let name2 = name(par1); // now name2 holds the second function and it has also the value of par1 given into first function.
	name(par2); // now we can call name2 and it will also use the previos given parameter par1.