Primitive Data, Operators,

primitiveData

We'll show how to initialize some primitive data here.

By primitive data, we mean non-object data (we'll learn about objects later).

let myNum1, myNum2, myString1, myString2, myString3,
		myBoolean1, myBoolean2;

//common number usage includes integers and floats
myNum1 = 5;
myNum2 = 10.99;

//strings
myString1 = 'we can use single quotes';
myString2 = "we can use double quotes";
myString3 = `or backticks (used for formatting)`;

//booleans (either true or false)
myBoolean1 = true;
myBoolean1 = false;

stringConcatenationJoining

String concatenation (joining) is done using the "+" operator.

let firstName, lastName, fullName;

firstName = 'Kofi';
lastName = 'Kingston';
//We add a space ' ' between the names
fullName = firstName + ' ' + lastName;
prn(fullName);

basicMathOps

The common arithmetic operators are the familiar +, -, * and /.

let a, b, c, sum, diff, product, quotient;

a = 10;
b = 2;

sum = a + b;
diff = a - b;
product = a * b;
quotient = a / b;

handyModulusRemainderOp

The modulus (remainder) operator (%) often comes in handy.

let a, b, remainder;

a = 5;
b = 3;
remainder = a % b;
prn("5/3 remainder (expecting 2): " + remainder);

incrementDecrement

The increment operator (++) will be a close friend on our js journey.

It's a concise abbreviated form.
"count++" is the same as "count = count + 1"

"count--" is the same as "count = count - 1"

//This is a line comment
let count;

count = 10;
prn('count (before): ' + count);

count++;
prn('count (after "++"): ' + count);

count--;
prn('count (after "--"): ' + count);

equality

Equality (equals) of prim values is done using the "===" operator and "not equals" is done using the "!==" operator.

There is also a "loose" version of each ("==" and "!=") but we generally prefer those above. We'll learn more details about the loose versions later.

//This is a line comment
let n1, n2, s1, s2, isEqual, isNotEqual;

n1 = 101;
n2 = 100 + 1;
//isEqual will be a boolean here (true/false)
isEqual = n1 === n2;
prn("isEqual (expecting true): " + isEqual);

s1 = 'foo';
s2 = 'oops';
//isEqual will be a boolean here (true or false)
isEqual = s1 === 22;
prn("isEqual (expecting false): " + isEqual);

s1 = 'foo';
s2 = 'oops';
isNotEqual = s1 !== 22;
prn("isNotEqual (expecting true): " + isNotEqual);