javascript - Difference Between indexOf and findIndex function of array

Question

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 the array where predicate is true, and -1 otherwise.

and

indexOf - Returns the index of the first occurrence of a value in an array.

Answer 1

The main difference are the parameters of these functions:

• Array.prototype.indexOf() expects a value as first parameter. This makes it a good choice to find the index in arrays of primitive types (like string, number, or boolean).

• Array.prototype.findIndex() expects a callback as first parameter. Use this if you need the index in arrays with non-primitive types (e.g. objects) or your find condition is more complex than just a value.

See the links for examples of both cases.