Operators in JavaScript Programming

JavaScript operators are symbols which are used to assign values, compare values, perform arithmetic operations, and more. 

• The variables (operations) are called operands.
• The operation (to be performed between the two operands) is defined by an operator.

JavaScript supports the following types of operators.

• Arithmetic Operators
• Comparison Operators
• Logical (or Relational) Operators
• Assignment Operators
• Conditional (or ternary) Operators
• String Operators
• Type Operators
• Bitwise Operators

JavaScript Arithmetic Operators –

Arithmetic operators perform arithmetic operations on numbers.

Example –

var x = 100 + 50;

// Addition
var a = 4;
var b = 3; 
var x = a + b; // adding 2 variables
var x = (100 + 50) * a; // expressions

// Subtraction
var x = 5;
var y = 2;
var z = x - y;

// Multiplication
var x = 5;
var y = 2;
var z = x * y;

// Division
var x = 5;
var y = 2;
var z = x / y;

// Modulo
var x = 5;
var y = 2;
var z = x % y;

// Increment
var x = 5;
x++;
var z = x;

// Decrement
var x = 5;
x--;
var z = x;

Associativity –

Associativity determines the way in which operators of the same precedence are parsed. For example, consider an expression:

a OP b OP c // OP means a operator

Left-associativity (left-to-right) means that it is processed as (a OP b) OP c, while right-associativity (right-to-left) means it is interpreted as a OP (b OP c).

Operator Precedence –

Operator precedence describes the order in which operations are performed in an arithmetic expression.

Example –

var x = 100 + 50 * 3;

As in traditional school mathematics, the multiplication is done first. Multiplication (*) and division (/) have higher precedence than addition (+) and subtraction (-).

JavaScript Comparison Operators –

Comparison and Logical operators are used to test for true or false.  Comparison operators are used in logical statements to determine equality or difference between variables or values.

Given that x = 5, the table below explains the comparison operators:

Example – 

if (age < 18) text = "Too young";
var voteable = (age < 18) ? "Too young":"Old enough"; // ternary operator

// if -else example
age = Number(age);
if (isNaN(age)) {
    voteable = "Input is not a number";
} else {
    voteable = (age < 18) ? "Too young" : "Old enough";
}

JavaScript Logical (or Relational) Operators –

Comparison and Logical operators are used to test for true or false.   Logical operators are used to determine the logic between variables or values.

Given that x = 6 and y = 3, the table below explains the logical operators:

JavaScript Assignment Operators –

Assignment operators assign values to JavaScript variables.

The **= operator is an experimental part of the ECMAScript 2016 proposal (ES7). It is not stable across browsers. Do not use it.

Example –

// The = assignment operator assigns a value to a variable.
var x = 10;

// The += assignment operator adds a value to a variable.
x += 5;

//The -= assignment operator subtracts a value from a variable.
var x = 10;
x -= 5;

// The *= assignment operator multiplies a variable.
var x = 10;
x *= 5;

// The /= assignment divides a variable.
var x = 10;
x /= 5;

// The %= assignment operator assigns a remainder to a variable.
var x = 10;
x %= 5;

JavaScript Conditional (Ternary) Operator –

JavaScript also contains a conditional operator that assigns a value to a variable based on some condition.

Syntax –

variablename = (condition) ? value1:value2 

Example –

var voteable = (age < 18) ? "Too young":"Old enough";

JavaScript String Operators –

The + operator can also be used to add (concatenate) strings.

var txt1 = "John";
var txt2 = "Doe";
var txt3 = txt1 + " " + txt2;

Output – 

John Doe

The += assignment operator can also be used to add (concatenate) strings:

var txt1 = "What a very ";
txt1 += "nice day";

Output – 

What a very nice day

Adding Strings and Numbers –

Adding two numbers, will return the sum, but adding a number and a string will return a string:

Example –

var x = 5 + 5;
var y = "5" + 5;
var z = "Hello" + 5;

Output –

10
55
Hello5

JavaScript Type Operators –

JavaScript Bitwise Operators –

Bit operators work on 32 bits numbers. Any numeric operand in the operation is converted into a 32 bit number. The result is converted back to a JavaScript number.

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