How To Learn Javascript ProperlyWeek 2 – Chapter 3

Since there’s so much to cover in week 2, I felt the need to break it up into 2 different post.

Here’s what I’ve learned just in chapter 3:

OPERATORS

“The logical NOT operator can also be used to convert a value into its Boolean equivalent.” so for example
```
alert(!!"blue"); //which results in true
```
is the same as writing
```
alert(Boolean("blue");
```
You can use “OR” operators in variables. For Example:
```
var result = true || false;
```

Unary operators initiate based on it’s location to the variable. For Example:

var num1 = 2;
var num2 = 20;
var num3 = num1-- + num2; //equals 22
var num4 = num1 + num2; //equals 21

When performing comparison operators on strings it checks the value of the first letter in the string and capitals are of lower value then lower case letters.
When comparing numbers that are in strings, the js interpreter will only convert them to integers if one of the two operands are an integer. For example:
```
var result = "23" < "3"; //true
var result = "23" < 3; //false
```

STATEMENTS

Funny how you think you know something till you get a better understanding of it…. do while statements will always execute the code block at least once before the expression is evaluated. (How I never retained that is sad).
Object properties in ECMAScript are unordered, so the order in which property names are returned in a for-in statement cannot necessarily be predicted. All enumerable properties will be returned once, but the order may differ across browsers.

Playing around with break and continue statements I ended up playing around with nested loops. I ended up writing this to help my brain wrap around the way the loops cycle through.

var num = 0;
outermost:
for (var i=0; i < 10; i++) {
console.log("the outer loop is now at " + i);
for (var j=0; j < 10; j++) {
if (i == 5 && j == 5) {
continue outermost;
}
console.log("the inner loop is now at " + j);
num++;
}
}
alert(num);

With loops are used on objects for efficiency, however they’re considered poor practice due to negative performance and debugging difficulties.
Writing a function that sometimes returns a value causes confusion, especially during debugging.
Functions doesn’t care how many arguments are passed in and the arguments can be called from within the function using the arguments[] object – There is alot to cover regarding how it works with named arguments and what not but I think it is incredibly powerful and useful. Here’s an example of something I wrote demonstrating this with the length method:
```
function sayHi() {
for(i=0; i<arguments.length; i++){
if(arguments[i] == "This is what I'm looking for!"){
alert(arguments[i]);
continue
}
console.log(arguments[i]);
}
}
sayHi("to this ","being concatenated", "and here", "This is what I'm looking for!",
"is some", "more arguments", "to test" );
```
Function overloading is not possible because of the lack of function signatures.