JavaScript Operators
An operator performs some operation on single or multiple operands (data value) and produces a result. For example 1 + 2, where the + sign is an operator 1 is a left operand and 2 is a right operand. The + operator adds two numeric values and produces a result which is 3 in this case.
JavaScript includes the following categories of operators.
- Arithmetic Operators
- Comparison Operators
- Logical Operators
- Assignment Operators
- Conditional Operators
Arithmetic Operators
Arithmetic operators are used to perform mathematical operations. Below are some arithmetic operators with a short description.
| Operator | Divide the left operand by right operand. |
|---|---|
| + | Adds two numeric operands. |
| – | Subtract the right operand from the left operand |
| * | Multiply two numeric operands. |
| / | Modulus operator. Returns the remainder of two operands. |
| % | Divide the left operand by the right operand. |
| ++ | Increment operator. Increase operand value by one. |
| — | Decrement operator. Decrease value by one. |
Example: Arithmetic Operators
var x = 6, y = 12, z = 15;
x + y; //returns 18
y - x; //returns 6
x * y; //returns 72
y / x; //returns 2
x % 2; //returns 0
x++; //returns 7
x--; //returns 5Comparison Operators
JavaScript language includes operators that compare two operands and return the Boolean value true or false.
| Operators | Description |
|---|---|
| == | Compares the equality of two operands without considering type. |
| === | Compares equality of two operands with type. |
| != | Compares inequality of two operands. |
| > | Check whether left side value is greater than the right side value. If yes then returns true otherwise false. |
| < | Check whether the left side value is greater than the right side value. If yes then returns true otherwise false. |
| >= | Check whether the left operand is less than the right operand. If yes then returns true otherwise false. |
| <= | Check whether the left operand is greater than or equal to the right operand. If yes then returns true otherwise false. |
Example: Comparison Operators
var a = 6, b = 12, c = "6";
var x = a;
a == c; // returns true
a === c; // returns false
a == x; // returns true
a != b; // returns true
a > b; // returns false
a < b; // returns true
a >= b; // returns false
a <= b; // returns true
a >= c; // returns true
a <= c; // returns trueLogical Operators
Logical operators are used to combine two or more conditions. JavaScript includes following logical operators.
| Operator | Description |
|---|---|
| && | && is known as AND operator. It checks whether two operands are non-zero (0, false, undefined, null or “” are considered as zero), if yes then returns 1 otherwise 0. |
| || | || is known as OR operator. It checks whether any one of the two operands is non-zero (0, false, undefined, null or “” is considered as zero). |
| ! | ! is known as NOT operator. It reverses the boolean result of the operand (or condition) |
Example: Logical Operators
var a = 5, b = 10;
(a != b) && (a < b); // returns true
(a > b) || (a == b); // returns false
(a < b) || (a == b); // returns true
!(a < b); // returns false
!(a > b); // returns trueAssignment Operators:
JavaScript includes assignment operators to assign values to variables with fewer keystrokes.
| Assignment operators | Description |
|---|---|
| = | Assigns right operand value to left operand. |
| += | Sums up left and right operand values and assign the result to the left operand. |
| -= | Subtract the right operand value from the left operand value and assign the result to the left operand. |
| *= | Multiply left and right operand values and assign the result to the left operand. |
| /= | Divide the left operand value by the right operand value and assign the result to the left operand. |
| %= | Subtract the right operand value from the left operand value and assign the result to the left operand. |
Example: Assignment operators
var x = 5, y = 10;
x = y; //x would be 10
x += 1; //x would be 11
x -= 1; //x would be 10
x *= 5; //x would be 50
x /= 5; //x would be 10
x %= 2; //x would be 0