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Does indexOf start 0 or 1?
The indexOf() method returns the first index at which a given element can be found in the array, or -1 if it is not present. Because arrays are 0 based, returning 0 would mean starting from the first character was matched; 1, the second character, and so on.
What does 1 mean in JavaScript?
-1 means the first goes before the second, 1 means it goes after, and 0 means they’re equivalent. The sort function uses the comparisons in the function you pass it to sort the function.
Which is faster includes or indexOf?
includes is around 50 times slower than indexOf, at least in Chrome.
Which is better indexOf or contains?
The contains method is implemented using a call to indexOf , so they are essentially the same. You should use whichever method makes your code more readable. If you are checking to see if a String contains a specific substring, use contains . If you are looking for the substring’s starting index, use indexOf .
What indexOf returns?
The indexOf() method returns the index within the calling String object of the first occurrence of the specified value, starting the search at fromIndex . Returns -1 if the value is not found.
What is return JS?
When a return statement is used in a function body, the execution of the function is stopped. If specified, a given value is returned to the function caller. For example, the following function returns the square of its argument, x , where x is a number.
Is indexOf fast?
EDIT: Based on more tests, indexOf seems to run faster than a for loop in the version of Safari I’m using (5.0. 3) and slower in just about everything else. It is also runnable. It shows that plain for loop is the best solution when considering performance.
Why use indexOf instead of includes?
I would suggest using the includes() method to check if the element is present in the array. If you need to know where the element is in the array, you need to use the indexOf() method.
Is regex faster than indexOf?
9 Answers. For just finding a keyword the IndexOf method is faster than using a regular expression. Regular expressions are powerful, but their power lies in flexibility, not raw speed. They don’t beat string methods at simple string operations.
What does indexOf return if not found?
indexOf() The indexOf() method returns the index within the calling String object of the first occurrence of the specified value, starting the search at fromIndex . Returns -1 if the value is not found.
What is indexOf () in JS?
The JavaScript indexOf() method returns the position of an item in a list or a substring in a string. The indexOf() method returns the first index at which a certain value can be found in an array or a string. If a value is not found, a special -1 value is returned.