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Performing math operations and calculus is a very common thing to do with any programming language.
JavaScript offers several operators to help us work with numbers.
- Addition (+)
- Subtraction (-)
- Division (/)
- Remainder (%)
- Multiplication (*)
- Exponentiation (**)
- Increment (++)
- Decrement (
--) - Unary negation (-)
- Unary plus (+)
Addition (+)
const three = 1 + 2
const four = three + 1
The + operator also serves as string concatenation if you use strings, so pay attention:
const three = 1 + 2
three + 1 // 4
'three' + 1 // three1
Subtraction (-)
const two = 4 - 2
Division (/)
Returns the quotient of the first operator and the second:
const result = 20 / 5 //result === 4
const result = 20 / 7 //result === 2.857142857142857
If you divide by zero, JavaScript does not raise any error but returns the Infinity value (or -Infinity if the value is negative).
1 / 0 //Infinity
-1 / 0 //-Infinity
Remainder (%)
The remainder is a very useful calculation in many use cases:
const result = 20 % 5 //result === 0
const result = 20 % 7 //result === 6
A reminder by zero is always NaN, a special value that means “Not a Number”:
1 % 0 //NaN
-1 % 0 //NaN
Multiplication (*)
Multiply two numbers
1 * 2 //2
-1 * 2 //-2
Exponentiation (**)
Raise the first operand to the power second operand
1 ** 2 //1
2 ** 1 //2
2 ** 2 //4
2 ** 8 //256
8 ** 2 //64
The exponentiation operator ** is the equivalent of using Math.pow(), but brought into the language instead of being a library function.
Math.pow(4, 2) == 4 ** 2
This feature is a nice addition for math intensive JS applications.
The ** operator is standardized across many languages including Python, Ruby, MATLAB, Lua, Perl and many others.
Increment (++)
Increment a number. This is a unary operator, and if put before the number, it returns the value incremented.
If put after the number, it returns the original value, then increments it.
let x = 0
x++ //0
x //1
++x //2
Decrement (--)
Works like the increment operator, except it decrements the value.
let x = 0
x-- //0
x //-1
--x //-2
Unary negation (-)
Return the negation of the operand
let x = 2
-x //-2
x //2
Unary plus (+)
If the operand is not a number, it tries to convert it. Otherwise if the operand is already a number, it does nothing.
let x = 2
+x //2
x = '2'
+x //2
x = '2a'
+x //NaN