Debugged into it and caught the exception at the point to get the stack
values:
```javascript
numSteps = 403
process = Object {ctor: "_Process", id: 39, root: null, stack: null, mailbox
: Array[0]}
```
So root is null, why would it be trying to access a null value without
checking if null?
Any ideas how to work around this in this project so I can at least keep
working in chrome?
On Wednesday, August 3, 2016 at 11:52:36 AM UTC-6, OvermindDL1 wrote:
>
> I keep getting this exception thrown from inside Elm, so far only from
> Chrome Version 51.0.2704.103 m
> ```
> elm.js:2417 Uncaught TypeError: Cannot read property 'ctor' of null
> ```
>
> Where that line and the surrounding context is purely Elm generated code,
> and is:
> ```javascript
> // STEP PROCESSES // Line 2411
>
> function step(numSteps, process)
> {
> while (numSteps < MAX_STEPS)
> {
> var ctor = process.root.ctor; // Line 2417 -- This is the error:
> Uncaught TypeError: Cannot read property 'ctor' of null
>
> if (ctor === '_Task_succeed')
> {
> while (process.stack && process.stack.ctor === '_Task_onError')
> {
> process.stack = process.stack.rest;
> }
> if (process.stack === null)
> ```
>
> The same javascript seems to run fine in firefox, IE, and edge, this only
> seems to happen in Chrome and only 'sometimes'. It seems to happen pretty
> quickly during loading and if it does not happen at the start then it does
> not seem to happen. I've not been able to find code to whittle down that
> lets my app still do anything while still causing this error.
>
> The 'step' function is being called from the 'work' function of (and with
> context):
> ```
> javascript
>
> // WORK QUEUE
>
> var working = false;
> var workQueue = [];
>
> function enqueue(process) {
> workQueue.push(process);
>
> if (!working) {
> setTimeout(work, 0);
> working = true;
> }
> }
>
> function work() {
> var numSteps = 0;
> var process;
> while (numSteps < MAX_STEPS && (process = workQueue.shift())) {
> numSteps = step(numSteps, process); // This is the place in the callstack
> before step
> }
> if (!process) {
> working = false;
> return;
> }
> setTimeout(work, 0);
> }
> ```
>
> Chrome is not reporting anything in the stack below `work` so this appears
> to be during the setTimeout callback set a few lines prior to work that
> calls work.
>
> Any thoughts as to the cause?
>
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