Javascript function not returning false

Question

This function is only returning true. I have added a console.log in the if block and it is called but the function doesn't return false.

function isUniform(List)
{
    var ele = List[0];
    List.forEach(function(item)
    {
        console.log(ele);
        if(ele !== item)
        {
            return false;
        }
    })
    return true;
}

Possible duplicate of How to short circuit Array.forEach like calling break? — JJJ
– JJJ, Commented Apr 18, 2017 at 10:21
Post a minimal verifiable example. How to create a Minimal, Complete, and Verifiable example — Pugazh
– Pugazh, Commented Apr 18, 2017 at 10:22

Nina Scholz · Accepted Answer · 2017-04-18 11:04:26Z

9

You need another method for testing unifomity. Better use Array#every, which checks every value with the first item of the array and return true, if all elements are equal and false if not. The iteration stops with the first unequal element.

function isUniform(list) {
    return list.every(function(item, _, array) {
        return item === array[0];
    });
}

The used Array#forEach returns always undefined:

forEach() executes the callback function once for each array element; unlike map() or reduce() it always returns the value undefined and is not chainable.

edited Apr 18, 2017 at 11:04

answered Apr 18, 2017 at 10:21

Nina Scholz

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Comments

muratoner · Accepted Answer · 2017-04-18 10:21:15Z

0

I think you can use this code;

function isUniform(List)
{
    var res = true;
    var ele = List[0];
    List.forEach(function(item)
    {
        console.log(ele);
        if(ele !== item)
        {
            res = false;
            return;
        }
    })
    return res;
}

answered Apr 18, 2017 at 10:21

muratoner

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1 Comment

Jaromanda X Over a year ago

the return; is as redundant as in the original question :p

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