The indexOf() method returns the first index (position) of a specified value. The indexOf() method returns -1 if the value is not found. The indexOf() method starts at a specified index and searches from left to right (from the given start postion to the end of the array).

Mar 13, 2025 · The indexOf() method of Array instances returns the first index at which a given element can be found in the array, or -1 if it is not present. Element to locate in the array. Zero-based index at which to start searching, converted to an integer.

Sep 8, 2011 · To find an index by object property: yourArray.findIndex(obj => obj['propertyName'] === yourValue) For example, there is a such array: let someArray = [ { property: 'OutDate' }, { property: 'BeginDate'}, { property: 'CarNumber' }, { property: 'FirstName'} ]; Then, code to find an index of necessary property looks like that:

Feb 10, 2025 · In JavaScript, an array is an ordered list of values. Each value is called an element, and each element has a numeric position in the array, known as its index. Arrays in JavaScript are zero-indexed, meaning the first element is at index 0, the second at index 1, and so on. 1. Create Array using Literal.

Apr 3, 2025 · JavaScript arrays are zero-indexed: the first element of an array is at index 0, the second is at index 1, and so on — and the last element is at the value of the array's length property minus 1. JavaScript array-copy operations create shallow copies.

Nov 18, 2024 · indexOf () returns the first index of a specified value in an array, or -1 if the value is not found. findIndex () is used for finding the index of an element based on complex conditions. It takes a callback function that can include any logic for locating an item within the array.

Sep 27, 2024 · The indexOf () method in JavaScript is used to find the position of the first occurrence of a specific value in an array. If the value is not present, it returns -1. This method is handy for quickly determining where a particular item is located within an array. element: This parameter holds the element whose index will be returned.

JavaScript Array indexOf() The indexOf() method searches an array for an element value and returns its position. Note: The first item has position 0, the second item has position 1, and so on.

Mar 19, 2025 · This chapter introduces collections of data which are ordered by an index value. This includes arrays and array-like constructs such as Array objects and TypedArray objects.

The Array indexOf() method returns the index of the first matching element in an array or -1 if there is no matching element. Here’s the syntax of the indexOf() method: const index = array .indexOf(searchElement, fromIndex) Code language: PHP ( php )