Uncaught TypeError: Cannot read property 'length' of undefined (if you enable scrollbars)

If I have hideScrollbar:false and scrollbars:true as an option and after a resize I reinitialise the iScroll (so I destroy it first and reinitialise it) with the same option I get this error if the scrollbars are true as soon as I switch this options to false the error doesn't happen but it does every time if I have the scrollbar options enabled as above.

[mr-moon]

Yeah, this happens prior to execution of scrollEnd event.

Uncaught TypeError: Cannot read property 'length' of undefined
    _indicatorsMap
    (anonymous function)
    IScroll._execEvent
    (anonymous function)

And if we look at what triggers it:

// Execute the scrollEnd event after 400ms the wheel stopped scrolling
clearTimeout(this.wheelTimeout);
this.wheelTimeout = setTimeout(function () {
    that._execEvent('scrollEnd');
    that.wheelTimeout = undefined;
}, 400);

It looks like this error raises when you have destroyed the iScroll object, but yet timer has not been cleared out.

[nim23]

I have the same problem when destroying and re-initialising IScroll. However the code that's causing the problem for me is the resize function.

 _resize: function () {
    var that = this;
    clearTimeout(this.resizeTimeout);
    this.resizeTimeout = setTimeout(function () {
        that.refresh();
    }, this.options.resizePolling);
}

As far as I can tell that.refresh() tries to update the scrollbar indicators and because it has already been removed from the DOM and from the IScroll object, IScroll throws an error. A simple check on the below function fixes the problem

function _indicatorsMap(fn) {
        if (that.indicators) { //check if indicators exist
            for (var i = that.indicators.length; i--;) {
                fn.call(that.indicators[i]);
            }
        }
    }

I think it's sensible to add the check, as I have seen on the other places IScroll does perform a check for the indicators.

[littletinyfish]

I can confirm that nim23's fix worked for me.

[rosko]

Hello. I got the same error when it tries to continue scrolling on inertia after destroying iScroll.

[benlwilliams]

nim23's fix worked for me as well.

[haskelcurry]

In case if someone is facing this issue and don't want to modify the source code of the lib, you can do this before the destroy:

scroll._events = {};

[rwhepburn]

+1 Experienced the same issue when using iScroll with Knockout JS.

[sculove]

@nim23 thank you. I merged on master branch.