TypeScript Switch case statement

TypeScript switch case statement Example:

Let's look at some switch case statements in action.

1) A normal TypeScript switch case example

A simple switch case example that displays a message based on the target ID is shown in the following example:

let targetID = 'btnDelete';

 
switch (targetID) {
    case 'btnUpdate':
        console.log('Update');
        break;
    case 'btnDelete':
        console.log('Delete');
        break;
    case 'btnNew':
        console.log('New');
        break;
}

Output:

delete

The targetID is set to btnDelete in this example.

The targetId is compared to a list of values in the switch case statement. The 'btnDelete' statement in the associated case clause executes since the targetID matches..

2) Grouping case example

If you have a code-shared by multiple cases, you can group them. For example:

// change the month and year
let month = 2,
    year = 2020;

 
let day = 0;
switch (month) {
    case 1:
    case 3:
    case 5:
    case 7:
    case 8:
    case 10:
    case 12:
        day = 31;
        break;
    case 4:
    case 6:
    case 9:
    case 11:
        day = 30;
        break;
    case 2:
        // leap year
        if (((year % 4 == 0) &&
            !(year % 100 == 0))
            || (year % 400 == 0))
            day = 29;
        else
            day = 28;
        break;
    default:
        throw Error('Month Invalid);
}
console.log(`The month ${month} in ${year} has ${day} days`);

Output:

The month 2 in 2020 has 29 days

The days of a certain month and year are returned in this example.

The count of days in a month will be 31 if the numbers are 1,3, 5, 7, 8, and 12. The count of days in a month will be 30 if it is 4, 6, 9, or 11.

It yields 29 days if the month is two and the year is a leap year. Otherwise, 28 days are produced.

Frequently Asked Questions

How does switch case work in TypeScript?

The switch statement is used to check for multiple values and executes sets of statements for each of those values. We must use the break keyword at the end of each case block to stop the execution of the case block.
 

Can we use string in the switch case of TypeScript?

The TypeScript switch statement executes one statement from multiple conditions. It evaluates an expression based on its value that could be Boolean, number, byte, short, int, long, enum type, string, etc.
 

Can cases in switch statements have conditions?

A statement in the switch block can be labeled with one or more case or default labels. An if-then-else statement can test expressions based on ranges of values or conditions, whereas a switch statement tests expressions based only on a single integer, enumerated value, or String object.

Key takeaways

The TypeScript switch statement combines numerous conditions into a single statement. It evaluates a Boolean, number, byte, short, int, long, enum type, string, and other expressions based on their value.