How to use Switch, break and default of JavaScript
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Break keyword
If JavaScript encounters a break keyword, it jumps out of the switch code block.
This will stop the execution of more code in the code block and case testing.
If a match is found and the task is completed, execution is randomly interrupted (break). No more tests are needed.
Break can save a lot of execution time because it "ignores" the execution of other code in the switch code block.
You don't have to interrupt the last case in the switch code block. The code block ends naturally here.
Default keyword
The default keyword specifies the code to run when there is no case match:
Example
The getDay () method returns the week name of the number 0 through 6.
If today is neither Saturday (6) nor Sunday (0), output a default message:
Switch (new Date (). GetDay () {
Case 6:
Text = "Today is Saturday"
Break
Case 0:
Text = "Today is Sunday"
Break
Default:
Text = "looking forward to the weekend -"
}
The result of text is:
Looking forward to the weekend--
The default case does not have to be the last case in the switch code block:
Example
Switch (new Date (). GetDay () {
Default:
Text = "looking forward to the weekend!"
Break
Case 6:
Text = "Today is Saturday"
Break
Case 0:
Text = "Today is Sunday"
}
If default is not the last case in the switch code block, remember to end the default case with break.
Common code blocks
Sometimes you need different case to use the same code.
In this example, case 4 and 5 share the same code block, while 0 and 6 share another code block:
Example
Switch (new Date (). GetDay () {
Case 4:
Case 5:
Text = "the weekend is coming:)"
Break
Case 0:
Case 6:
Text = "Today is the weekend -"
Break
Default:
Text = "looking forward to the weekend!"
}
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