What is wrong with my javascript functions logic?

Question

I'm having a problem with my Javascript function, I'm not understanding something, just looking for some clarity.

I have a function:

function Test (array) {
    if (array === []) {
        return "the array is empty";
    } else {
    return array;
}

When I pass this function an empty array, it returns the empty array, completely skipping the first part of my if statement (this is the part I'm not understanding, why is it skipping that part? My understanding is that it would return my string statement at that point since the array I pass it, is in fact empty. If I remove the else statement, it returns "undefined".

NOTE! : I am aware that the solution to this problem is to set my "if" statement to compare the length of the array I pass it.

ex:

function Test (array) {
    if (array.length === 0) {
        return "the array is empty";
    } else {
    return array;
}

I'm just still not understanding why the first one doesn't work, and would really appreciate an explanation.

`if (array === []) {` will never be true. But `if (array.length === 0)` will be true for an empty array. — T.J. Crowder, Nov 28 '16 at 16:42
You cannot compare two arrays. Both have different addresses. Arrays are not immutable objects. They are just references. — Praveen Kumar Purushothaman, Nov 28 '16 at 16:42

score 3 · Accepted Answer · answered Nov 28 '16 at 16:41

3

When you compare two objects in JavaScript, the comparison is asking "Are these objects the same object?", not "Are these objects identical?".

You are comparing two different empty arrays.

answered Nov 28 '16 at 16:41

Quentin

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What is wrong with my javascript functions logic?

1 Answers1