JavaScript Array Search Functions Explained with Local Storage | 8 Must-Know Methods for Interview

In this video, learn how to search through JavaScript arrays using 8 powerful methods — ideal for both primitive arrays and arrays of objects.
We’ll also show how to store and retrieve filtered or matched results using localStorage for real-world web apps.

What You'll Learn:
some() – Checks if at least one element satisfies the condition. Great for validation or conditional logic.

find() – Returns the first object that matches the condition. Useful for quick lookups in object arrays.

findIndex() – Returns the index of the first matching element or -1 if not found. Ideal for editing or removing items.

filter() – Returns a new array with all elements that match. Use it for multi-result searches.

every() – Checks if all elements in the array pass a test. Helpful for global conditions.

includes() – Checks if a specific primitive value exists in the array. Simple and fast.

indexOf() – Finds the index of the first occurrence of a primitive value. Returns -1 if not found.

lastIndexOf() – Similar to indexOf(), but searches from the end of the array. Useful for reverse checks.