javascript string method lastIndexOf()

Asked Dec 05 '22 at 18:41

Active Dec 05 '22 at 18:44

Viewed 14 times

I've been checking the lastIndexOf() method. Can someone explain the fourth case? The result is a bit strange, it shouldn't be -1 right?

let study = "javascript";
console.log(study.length); // 10
// search chr only
console.log(study.lastIndexOf('t')); // 9; 't' is found at index 9
console.log(study.lastIndexOf('v')); // 2; 'v' is found at index 2
console.log(study.lastIndexOf()); // -1; [empty] is not found
console.log(study.lastIndexOf("")); // 10; [nothing] is found at index 10, strange result
console.log(study.lastIndexOf(" ")); // -1; space is not found

edited Dec 05 '22 at 18:43

David

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asked Dec 05 '22 at 18:41

Paco67

What should be the result in your opinion? – Konrad Dec 05 '22 at 18:43
Same reason why `split("")` works. Nothing is found after every character, so naturally the last index it can be found is after the 10th character, index 10. – tobimori Dec 05 '22 at 18:44
thank you. I have search a similar question first. Sorry. – Paco67 Dec 05 '22 at 18:51

javascript string method lastIndexOf()

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