Operators in Javascript

Rumman Ansari   Software Engineer   2023-03-26   6258 Share
☰ Table of Contents

Table of Content:

Following operators available in JavaScript:

  • Assignment operators
  • Arithmetic operators
  • Comparison operators
  • Logical operators
  • String operators
  • Conditional operators
Assignment Operators
  • Like most programming languages, = is the assignment operator
  • Variables can be declared either by key var and value OR simply by assigning values directly. Ex – var x = 42; OR x = 42 ;
  • Explicit type declaration is not necessary.
  • Same variable can be assigned values of different data types. To know the type of a variable, use typeof operator. Ex –
        var x = "hello"; 
        var x = true;
        console.log(typeof x); //returns Boolean
Comparison Operators
  • JavaScript has operators like <, >, !=, >=, <= to compare 2 operands.
  • What is unique about JavaScript is the == and === operators?
  • == compares the operands and returns true without considering their data type. Ex: var a = 10, b= “10”;
  • if(a==b) results in true due to the same value they carry, but ignores data types differentiation.
  • However, if(a===b) results in false as they are of different data types.
Standard Arithmetic Operators
  • Addition + Ex: [5 + 8]
  • Subtraction - Ex: [49 – 38]
  • Division / Ex: [ 49 / 7]
  • Multiplication * Ex: [28 * 2]

 

More on Arithmetic Operators
  • Modulus % to return the remainder of a division – Ex: 50 % 7 is 1
  • Increment ++ to increment the operand itself by 1 – Ex: If x=4, x++ evaluates to 5
  • Decrement -- to decrement the operand itself by 1 – Ex: if x= 10, x—- evaluates to 9 
Logical Operators

AND &&, OR ||, NOT ! are the logical operators often used during conditional statements to test logic between variables.

  • Expr1 && Expr2 returns true if both are true, else returns false.
  • Expr1 || Expr2 returns true if either is true.
  • !Expr1 operates on single operand to convert true to false and vice versa.
String Operator

Operator + is used to concatenate strings. x = "Hello"; y = " World "; x + y; /* Returns “Hello World” */

While concatenating, JavaScript treats all data types as strings even if values are of different data types.

 x = "Hello";
y = 100;
z = 333;
x + y + z;  /*  Returns “Hello100333” */
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