Video: https://youtu.be/5pRWaIOAxyk
Code from this video: https://jsfiddle.net/s28jmn4q/6/
Operators summary
In programming world, operators are reserved symbols that you can use to perform mathematical or logical operations. You can use them for arithmetic or for checking if a variable is equal to a value or to another variable and much more of course.
The following are the common types of operators that you will usually be working with:
Arithmetic
We can use arithmetic operators to perform operations such as addition, subtraction, multiplication and division.
| Symbol | Operation | Usage | Details |
|---|---|---|---|
| + | addition | x + y | add y to x |
| - | subtraction | x - y | subtract y from x |
| * | multiplication | x * y | multiply x with y |
| / | division | x / y | divide x by y |
// Addition
let a = 5 + 5
console.log(a) // 10
// Subtraction
let s = 10 - 5
console.log(s) // 5
// Multiplication
let m = 5 * 2
console.log(m) // 10
// Division
let d = 4 / 2
console.log(d) // 2Assignment
You already saw one example of this in the previous section where we went over variables - that is assigning a value to a variable. We have a few more assignment operators than just the = one.
| Symbol | Operation | Usage | Same as | Details |
|---|---|---|---|---|
| = | assignment | x = y | assignes whatever value is in y to x |
|
| += | add and assignment | x += y | x = x + y | assignes to x the result of adding y to x |
| -= | minus and assignment | x -= y | x = x - y | assignes to x the result of minusing y from x |
| *= | multiply and assignment | x *= y | x = x * y | assignes to x the result of multiplying x with y |
| /= | divide and assignment | x /= y | x = x / y | assignes to x the result of dividing x by y |
// Assignment
let name = "John Doe"
console.log(name) // John Doe
// Add and assignment
let x = 5
x += 5 // x = 5 + 5
console.log(x) // 10
// Minus and assignment
let x = 5
x -= 3 // x = 5 - 3
console.log(x) // 2
// Multiply and assignment
let x = 5
x *= 2 // x = 5 * 2
console.log(x) // 10
// Divide and assignment
let x = 4
x /= 2 // x = 4 / 2
console.log(x) // 2Comparison
We use comparision operators to do comparisons. They result to either a true or false value (Boolean) based on whatever comparision is being made. For example, we can use comparision operators to check if two variables are equal or unequal.
| Symbol | Operation | Usage | Details |
|---|---|---|---|
| == | equal | x == y | checks if x equals y - If equals the comparision results to true |
| != | not equal | x != y | checks if x does not equal y - If not equals the comparision results to true |
| > | greater than | x > y | checks if x is greater than y - If greater the comparision results to true |
| < | less than | x < y | checks if x is less than y - If lesser the comparision results to true |
| >= | greater than or equal | x >= y | checks if x is greater than or equal to y - If is greater than or equal the comparision results to true |
| <= | less than or equal | x <= y | checks if x is less than or equal to y - If is less than or equal the comparision results to true |
// Equal
console.log(5 == 5) // true
console.log(5 == 4) // false
// Not equal
console.log(5 != 6) // true
console.log(5 != 5) // false
// Greater than
console.log(5 > 4) // true
console.log(5 > 6) // false
// Less than
console.log(5 < 6) // true
console.log(5 < 4) // false
// Greater than or equal
console.log(5 >= 5) // true
console.log(5 >= 4) // true
console.log(5 >= 6) // false
// Less than or equal
console.log(5 <= 5) // true
console.log(5 <= 6) // true
console.log(5 <= 2) // false