How and Why to Avoid ‘for’ Loops

👋 Ciprian on Wednesday, January 17, 2018 in Blog, JavaScript
Last modified on Monday, January 8, 2018

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Never again use for() for looping. Using for() can be dangerous, especially if you use a library which adds attributes to native objects. If you use jQuery, do loops with $.each(). Change this loop:

for (i in my_array_or_object) {
    if (my_checking_function(my_array_or_object[i])) {
        break;
    }
}

or

for (i = 0; i < my_array.length; ++i) {
    if (my_checking_function(my_array[i])) {
        break;
    }
}

to

$.each(my_array_or_object, function(i, value) {
    if (my_checking_function(value)) {
        return false;
    }

    return true;
});

If the circumstances force you to use a for() loop, do it this way:

for (i in my_object) {
    if (!my_object.hasOwnProperty(i)) {
        continue;
    }

    if (my_checking_function(my_object[i])) {
        break;
    }
}

Find more JavaScript tutorials, code snippets and samples here or more jQuery tutorials, code snippets and samples here.

Find more JavaScript tutorials, code snippets and samples here or more jQuery tutorials, code snippets and samples here.

👋 Added by Ciprian on Wednesday, January 17, 2018 in Blog, JavaScript. Last modified on Monday, January 8, 2018.

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