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 …

Jun 16, 2019 · If your situation requires the use of a regular expression, use the search() method, otherwise; the indexOf() method is more performant.

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"));

2 You can use the fromIndex of Array#indexOf. fromIndex The index to start the search at. If the index is greater than or equal to the array's length, -1 is returned, which means the array will …

In javascript, is there an equivalent of String.indexOf (...) that takes a regular expression instead of a string for the first parameter, while still allowing a second parameter ? I need to do some...

Dec 20, 2017 · 1 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 > -1 is another way of saying …

.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) …

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.

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.