How to find the index of an element in an array in JavaScript
Łukasz Holeczek
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Finding the index position of elements in arrays is essential for data manipulation, conditional logic, and implementing features like highlighting, sorting, or removing specific items in JavaScript applications.
With over 25 years of experience in software development and as the creator of CoreUI, I’ve implemented index searching extensively in components like sortable lists, selection systems, and data tables where precise element positioning is crucial.
From my extensive expertise, the most straightforward and efficient solution is using the indexOf() method for primitive values, which returns the first occurrence’s index.
This approach is fast, widely supported, and specifically designed for finding element positions.
How to check if an array contains a value in JavaScript
Łukasz Holeczek
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Checking whether an array contains a specific value is fundamental for validation, conditional logic, and user interface states in modern JavaScript applications.
With over 25 years of experience in software development and as the creator of CoreUI, I’ve implemented this check thousands of times in components like permission systems, feature toggles, and form validation where specific values determine application behavior.
From my extensive expertise, the most modern and efficient solution is using the ES6 includes() method, which provides a clean boolean return value.
This approach is readable, performant, and specifically designed for membership testing.