Javascript For..In loop executing both the if and else statement
Question
I have this if statement with an else block and they are both inside a for in loop. When I execute this it always return both the value from the if statement and the else statement. Shouldn't it only go to the else block when the if statement is false?
<!DOCTYPE html> <html> <body> <p>Click the button to begin</p> <button onclick="myFunction()">Try it</button> <script> const moodList = { sad: { quotes: ['this is a sad quote', 'this is a sad quote number 2', 'this is a sad quote number 3' ] }, happy: { quotes: ['this is a happy quote', 'this is a happy quote number 2', 'this is a happy quote number 3' ] } } function myFunction() { let moodInput = prompt('Enter a feeling'); for (var key in moodList) { if (moodInput.includes(key)) { console.log('you got a result!'); } else { console.log('nothing'); } } } </script> </body> </html>
2 answers
solution1
2 2017-04-03 16:16:54
Instead of creating a loop over the object, you could check to see if the value entered is a key on the object:
if (moodList[moodInput]) {
console.log('you got a result!');
} else {
console.log('nothing');
}
Updated Code:
const moodList = { sad: { quotes: ['this is a sad quote', 'this is a sad quote number 2', 'this is a sad quote number 3' ] }, happy: { quotes: ['this is a happy quote', 'this is a happy quote number 2', 'this is a happy quote number 3' ] } } function myFunction() { let moodInput = prompt('Enter a feeling'); if (moodList[moodInput]) { console.log('you got a result!'); } else { console.log('nothing'); } }
<p>Click the button to begin</p> <button onclick="myFunction()">Try it</button>
solution2
1 2017-04-03 16:19:19
You could use the key and check if the key is in the object with the in operator .
const moodList = { sad: { quotes: ['this is a sad quote', 'this is a sad quote number 2', 'this is a sad quote number 3' ] }, happy: { quotes: ['this is a happy quote', 'this is a happy quote number 2', 'this is a happy quote number 3' ] } }; function myFunction() { let moodInput = prompt('Enter a feeling'); if (moodInput in moodList) { console.log('you got a result!'); } else { console.log('nothing'); } }
<p>Click the button to begin</p> <button onclick="myFunction()">Try it</button>
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.
Related Question
JavaScript: else statement inside a for..in loop is breaking my if statement
If statement executing both if and else
If and else both statement executing
Loop executing both if and else
Both the if and else statement are executing together
JavaScript Object for..in loop
Both if and else are executing Javascript/JQuery
javascript executing both if else blocks
Javascript for..in vs for loop performance
If and Else statement are both running in javascript
Related Tags