[英]Javascript For..In loop executing both the if and else statement
我有一個帶有else塊的if語句，它們都在for循環中。 當我執行它時，它總是返回if語句和else語句中的值。 當if語句為false時，它不應該只轉到else塊嗎？
<!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>
您可以檢查輸入的值是否是對象上的鍵，而不是在對象上創建循環：
if (moodList[moodInput]) {
console.log('you got a result!');
} else {
console.log('nothing');
}
更新的代碼：
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>
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>
JavaScript：for..in循環中的else語句破壞了我的if語句
[英]JavaScript: else statement inside a for..in loop is breaking my if statement
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