Question

105

Javascript TypeError: Cannot read property 'indexOf' of undefined

rated 0 times [ 106] [ 1] / answers: 1 / hits: 120815 / 8 Years ago, fri, january 27, 2017, 12:00:00

In this code I want to remove an element from the cart_products array.

var cart_products = [17^1, 19^1, 18^1];

var product = 17;



$.each(cart_products,function(key, item) {

    if(item.indexOf(product+^) !== -1){

        cart_products.splice(key, 1);

    }

});

But I get this error in Google Chrome console:

Uncaught TypeError: Cannot read property 'indexOf' of undefined

Is there something wrong with the code?

Thanks for your help.

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hayleevalenciac

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2 Years ago

answered 8 Years ago cartersinceren · Accepted Answer

The problem is that you're modifying the array while jQuery's $.each is looping over it, so by the time it gets to the end, the entry that used to be at index 2 is no longer there. (I admit I'm a bit surprised $.each behaves that way, but I haven't used $.each in at least five years, so...)

If the goal is to remove matches from the array, the better choice is filter:

var cart_products = [17^1, 19^1, 18^1];

var product = 17;



cart_products = cart_products.filter(function(item) {

    return item.indexOf(product+^) === -1;

});

console.log(cart_products);

...or alternately if it's important to modify the array in-place rather than creating a new one use a boring for loop as Andreas points out looping backward through the array so it doesn't matter when you remove things:

var cart_products = [17^1, 19^1, 18^1];

var product = 17;



var target = product + ^;

for (var index = cart_products.length - 1; index >= 0; --index) {

  if (cart_products[index].indexOf(target) !== -1) {

    cart_products.splice(index, 1);

  }

}

console.log(cart_products);