How to use the switch statement in JavaScript
The switch statement is used to control the flow of a program and is a part of JavaScript’s conditional statements.
It allows the execution of a specific code block depending upon the evaluation of an expression.
The structure of switch
- The switch structure starts with the
switchkeyword followed by the expression to be evaluated in parentheses.
switch (expression){}
- Inside the curly braces different cases are defined followed by a value to be strictly matched with the evaluated expression.
switch (expression){case value1:/* implement the statement(s) to be executed whenexpression = value1 */break;case value2:/* implement the statement(s) to be executed whenexpression = value2 */break;case value3:/* implement the statement(s) to be executed whenexpression = value3 */break;default:/* implement the statement(s) to be executed if expressiondoesn't match any of the above cases */}
-
The
breakstatement is used to exit the switch structure after the execution of a case. If it is not used, all the subsequent cases will be executed until the program encounters anybreakstatement or the ending curly brace}of the structure. -
The
default:is a special type of case and is executed when none of the cases match the evaluated expression.
Example
The program will find out the day of the week based on the value of the day variable.
Let’s look at the flow chart of this example for a better understanding:
Let’s look at the implementation of the example:
var day = 2; //change and try with different valuesswitch(day){case 1: //if day = 1console.log("Monday");break;case 2: //if day = 2console.log("Tuesday");break;case 3: //if day = 3console.log("Wednesday");break;case 4: //if day = 4console.log("Thursday");break;case 5: //if day = 5console.log("Friday");case 6: //if day = 6console.log("Saturday");case 7: //if day = 7console.log("Sunday");break;default: //if day doesn't match any of aboveconsole.log("Invalid");}
