The confusion between arrays being undefined or having a value of -

Can you explain the disparity between the two results produced by this code snippet:

var animals = ["a", "b", "c", "d"];

console.log = [4];
console.log(animals.indexOf("e"));

Specifically, why does it display 'undefined' instead of '-1' for indexOf?

Answer №1

The method indexOf() searches for the element "e" within the array. If the element is found, it will return the index at which it is located; otherwise, it will return -1.

Assigning [4] to console.log with the expression console.log = [4] replaces the original function console.log() with an array containing a single value of 4.

Answer №2

Here is the corrected version of the code snippet:

let animalArr = ["a", "b", "c", "d"];
console.log(animalArr.indexOf("e"));

The code now functions as intended.

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