17 I like Pablo's answer, but Array#indexOf and Array#map don't work on all browsers. Underscore will use native code if it's available, but has fallbacks as well. Plus it has the pluck …

Jan 3, 2017 · I am confused between the difference between the two function indexOf and find Index in an array. The documentation says findIndex - Returns the index of the first element in …

Jan 1, 2022 · The indexOf function of a string does not return a character but rather returns the position of the first place that string or character is found, not the character itself.

Dec 21, 2011 · I am learning Javascript and don't understand why the indexOf below returns -1: var string = "The quick brown fox jumps over the lazy dog"; console.log (string.indexOf("good"));

Dec 20, 2017 · indexOf returns a -1 if the search is not in the string. This is because indexOf will return the position of the search term in the string. For example is another way of saying …

Dec 9, 2008 · If your situation requires the use of a regular expression, use the search() method, otherwise; the indexOf() method is more performant.

.indexOf() and .includes() methods can be used to search for an element in an array or to search for a character/substring in a given string. Usage in Array (Link to ECMAScript Specification) …

List<T>.IndexOf looks for an item in the list which is equal to the value you pass it. By default, for classes, equality is simply object identity - so two different objects are treated as unequal, …

Apr 14, 2013 · var numberList = [100,200,300,400,500]; var index = numberList.indexOf(200); // 1 You will get -1 if it cannot find a value in the array.

Sep 23, 2010 · The NodeList don't have a indexOf(element) method? So, how can I get the element index?