# Function crashing node-red - Fatal JavaScript invalid size error

**URL:** <https://discourse.nodered.org/t/function-crashing-node-red-fatal-javascript-invalid-size-error/64549>\
**Category:** General\
**Tags:** function-node\
**Created:** [30 June 2022 15:29 UTC](https://discourse.nodered.org/t/function-crashing-node-red-fatal-javascript-invalid-size-error/64549 "2022-06-30T15:29:08Z")\
**Posts on this page:** 13\
**Page:** 1

<div class="post-metadata">

**Author:** ![HaroldPetersInskipp](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/haroldpetersinskipp/32/42319_2.png) [@HaroldPetersInskipp](https://discourse.nodered.org/u/HaroldPetersInskipp)\
**Post date:** [30 June 2022 15:29 UTC](https://discourse.nodered.org/t/function-crashing-node-red-fatal-javascript-invalid-size-error/64549/1 "2022-06-30T15:29:08Z")

</div>

I have a `function` node containing the following code:

```auto
// set number of boxes/prisoners
const MaxPrisoners = 20;

// create PrisonerBoxes array
let PrisonerBoxes = [];

// set which box/prisoner to start from
const startingNumber = msg.payload - 1;

// create Loop array
const Loop = [];

// fill PrisonerBoxes with values
for (let i = 1; i <= MaxPrisoners; i++) {
    PrisonerBoxes.push(i);
};

// shuffle values in array of PrisonerBoxes
let res = PrisonerBoxes.slice(0);
for (let j, x, i = res.length; i; j = Math.floor(Math.random() * i), x = res[--i], res[i] = res[j], res[j] = x);
PrisonerBoxes = res;

// get value in the currently open box
let boxValue = PrisonerBoxes[startingNumber];

// set value of nextBox to open
let nextBoxValue = boxValue;

// iterate through boxes until starting value is found
for (let i = startingNumber; i != boxValue; i = nextBoxValue - 1) {
    if (PrisonerBoxes[i]) {
        Loop.push(PrisonerBoxes[i]);
        nextBoxValue = PrisonerBoxes[i];
        boxValue = PrisonerBoxes[nextBoxValue];
    };  
};

// display the resulting Loop as msg.loop
msg.loop = Loop;

// display the resulting PrisonerBoxes as msg.boxes
msg.boxes = PrisonerBoxes;

// return the msg object
return msg;

```

Sometimes when it runs I get a return like this:

```auto
{
"_msgid":"e03a58c68912c40b",
"payload":5,
"loop":[17,7,2,3,16,20,14,18,6,11,9,15,10],
"boxes":[13,3,16,5,17,11,2,4,15,1,9,12,8,18,10,20,7,6,19,14]
}

```

But other times I get this in the console output

```auto
# Fatal error in , line 0
# Fatal JavaScript invalid size error 169220804
#
#
#
#FailureMessage Object: 00000080594FD2E0
 1: 00007FF747E11B4F v8::internal::CodeObjectRegistry::~CodeObjectRegistry+115135
 2: 00007FF747D2EA2F std::basic_ostream<char,std::char_traits<char> >::operator<<+64591
 3: 00007FF748AF2432 V8_Fatal+162
 4: 00007FF748664D85 v8::internal::FactoryBase<v8::internal::Factory>::NewFixedArray+101
 5: 00007FF74852206E v8::debug::Script::GetIsolate+16350
 6: 00007FF7483937CD v8::internal::CompilationCache::IsEnabledScriptAndEval+27293
 7: 00007FF74883F6A1 v8::internal::SetupIsolateDelegate::SetupHeap+513649
 8: 0000019DF2F6D8B3

```

I'm still somewhat new to JS and Node-RED, normally errors give me something to go off of, but I'm stumped here. Am I doing something to an array wrong? or is it something else?

Happens on a Raspberry Pi 4, Node-RED 2.2.2 node v16.15.1 npm v8.11.0  
and on Windows 10 build 21H2, Node-RED 2.1.4 node v17.6.0 npm v8.3.0

---

<div class="post-metadata">

**Author:** ![Steve-Mcl](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/steve-mcl/32/4826_2.png) [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)\
**Post date:** [30 June 2022 15:40 UTC](https://discourse.nodered.org/t/function-crashing-node-red-fatal-javascript-invalid-size-error/64549/2 "2022-06-30T15:40:47Z")

</div>

> [@HaroldPetersInskipp](#):
>
> ```auto
> for (let i = startingNumber; i != boxValue; i = nextBoxValue - 1) {
> if (PrisonerBoxes[i]) {
> Loop.push(PrisonerBoxes[i]);
> nextBoxValue = PrisonerBoxes[i];
> boxValue = PrisonerBoxes[nextBoxValue];
> };  
> }
> 
> ```

My money is on this part of the code. I believe if `PrisonerBoxes[i]` is empty or zero, you will have an infinite loop.

---

<div class="post-metadata">

**Author:** ![TotallyInformation](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/totallyinformation/32/31_2.png) [@TotallyInformation](https://discourse.nodered.org/u/TotallyInformation)\
**Post date:** [30 June 2022 15:43 UTC](https://discourse.nodered.org/t/function-crashing-node-red-fatal-javascript-invalid-size-error/64549/3 "2022-06-30T15:43:43Z")

</div>

> [@HaroldPetersInskipp](#):
>
> `// iterate through boxes until starting value is found`

I would have thought that an Array filter would have been a lot more efficient here.

---

<div class="post-metadata">

**Author:** ![Colin](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/colin/32/17040_2.png) [@Colin](https://discourse.nodered.org/u/Colin)\
**Post date:** [30 June 2022 15:47 UTC](https://discourse.nodered.org/t/function-crashing-node-red-fatal-javascript-invalid-size-error/64549/4 "2022-06-30T15:47:13Z")

</div>

Also it is dangerous to test for equality for the end of a loop, just in case you start off the wrong side of the end value. It is safer always to use, for example, `<=`

---

<div class="post-metadata">

**Author:** ![HaroldPetersInskipp](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/haroldpetersinskipp/32/42319_2.png) [@HaroldPetersInskipp](https://discourse.nodered.org/u/HaroldPetersInskipp)\
**Post date:** [30 June 2022 15:52 UTC](https://discourse.nodered.org/t/function-crashing-node-red-fatal-javascript-invalid-size-error/64549/5 "2022-06-30T15:52:25Z")

</div>

Sorry, I should have specified that my inspiration for this exercise is a Veritasium video about the 100 Prisoners Riddle: [The Riddle That Seems Impossible Even If You Know The Answer - YouTube](https://www.youtube.com/watch?v=iSNsgj1OCLA)

So in trying to recreate the conditions I believe I need to form a loop through iteration.

---

<div class="post-metadata">

**Author:** ![HaroldPetersInskipp](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/haroldpetersinskipp/32/42319_2.png) [@HaroldPetersInskipp](https://discourse.nodered.org/u/HaroldPetersInskipp)\
**Post date:** [30 June 2022 15:53 UTC](https://discourse.nodered.org/t/function-crashing-node-red-fatal-javascript-invalid-size-error/64549/6 "2022-06-30T15:53:29Z")

</div>

I see, this sounds like good advice, I will try to implement this from now on.

---

<div class="post-metadata">

**Author:** ![Steve-Mcl](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/steve-mcl/32/4826_2.png) [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)\
**Post date:** [30 June 2022 16:57 UTC](https://discourse.nodered.org/t/function-crashing-node-red-fatal-javascript-invalid-size-error/64549/7 "2022-06-30T16:57:45Z")

</div>

Here is a low(ish) code version (i'm certain given a little more time I could remove more function code)

![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/7/6/763051a29be96ec7b298059019de8ec75248fba6.png)

 ![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/a/3/a34bb2f64de79bf0e998becb3aab2cb7b7bec076.png)

```auto
[{"id":"243a9ac0bbe5e22f","type":"inject","z":"10ece3ab98e93683","name":"Start (shuffle and go)","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"","payloadType":"date","x":1750,"y":120,"wires":[["637f709011eba368"]]},{"id":"637f709011eba368","type":"function","z":"10ece3ab98e93683","name":"Shuffle Boxes","func":"function shuffle(array) {\n let currentIndex = array.length, randomIndex;\n while (currentIndex != 0) {\n // Pick a remaining element.\n randomIndex = Math.floor(Math.random() * currentIndex);\n currentIndex--;\n [array[currentIndex], array[randomIndex]] = [\n array[randomIndex], array[currentIndex]];\n }\n return array;\n}\n\nconst boxes = []\nfor (let index = 0; index < 100; index++) {\n boxes[index] = (index+1);\n}\n\nmsg.payload = [null, ...shuffle(boxes)]\nreturn msg;","outputs":1,"noerr":0,"initialize":"","finalize":"","libs":[],"x":1950,"y":120,"wires":[["cacc208e1ee151c9"]]},{"id":"ce9926bcb0cd73ec","type":"split","z":"10ece3ab98e93683","name":"","splt":"\\n","spltType":"str","arraySplt":1,"arraySpltType":"len","stream":false,"addname":"","x":1990,"y":180,"wires":[["ff5fb633b49f7224"]]},{"id":"199b437c3249eff8","type":"join","z":"10ece3ab98e93683","name":"","mode":"auto","build":"object","property":"payload","propertyType":"msg","key":"topic","joiner":"\\n","joinerType":"str","accumulate":"false","timeout":"","count":"","reduceRight":false,"x":1810,"y":240,"wires":[["435a284bd18dfd3f"]]},{"id":"ff5fb633b49f7224","type":"function","z":"10ece3ab98e93683","name":"Look for box","func":"\nconst boxes = flow.get(\"boxes\");\nconst prisonerNo = msg.payload;\nlet boxToCheck = prisonerNo;\n\nmsg.payload = false; //assume failure\n\nfor (let index = 0; index < 50; index++) {\n const inBox = boxes[boxToCheck]\n if (inBox === prisonerNo) {\n msg.payload = true\n break\n }\n boxToCheck = inBox;\n}\n\nreturn msg;","outputs":1,"noerr":0,"initialize":"","finalize":"","libs":[],"x":2150,"y":180,"wires":[["199b437c3249eff8"]]},{"id":"435a284bd18dfd3f","type":"function","z":"10ece3ab98e93683","name":"calc result","func":"const results = msg.payload\nmsg.payload = {}\n\nmsg.payload.results = results.map((e, i) => {\n return {\n prisonerNo: i+1,\n result: e\n }\n})\n\nmsg.payload.losers = msg.payload.results.filter(e => e.result == false)\nmsg.payload.winners = msg.payload.results.filter(e => e.result == true)\nmsg.payload.prisonerCount = msg.payload.results.length\nmsg.payload.loserCount = msg.payload.losers.length\nmsg.payload.winnerCount = msg.payload.winners.length\nmsg.payload.result = msg.payload.winnerCount === msg.payload.prisonerCount ? \"freedom\" : \"death\"\nreturn msg;","outputs":1,"noerr":0,"initialize":"","finalize":"","libs":[],"x":1980,"y":240,"wires":[["8533858cd09afb66"]]},{"id":"8533858cd09afb66","type":"debug","z":"10ece3ab98e93683","name":"Life or death","active":true,"tosidebar":true,"console":false,"tostatus":true,"complete":"payload","targetType":"msg","statusVal":"payload","statusType":"auto","x":2150,"y":240,"wires":[]},{"id":"1186a8b946b1d714","type":"change","z":"10ece3ab98e93683","name":"Lineup prisoners","rules":[{"t":"set","p":"payload","pt":"msg","to":"[1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100]","tot":"json"}],"action":"","property":"","from":"","to":"","reg":false,"x":1810,"y":180,"wires":[["ce9926bcb0cd73ec"]]},{"id":"cacc208e1ee151c9","type":"change","z":"10ece3ab98e93683","name":"","rules":[{"t":"set","p":"boxes","pt":"flow","to":"payload","tot":"msg"}],"action":"","property":"","from":"","to":"","reg":false,"x":2140,"y":120,"wires":[["1186a8b946b1d714"]]}]

```

---

<div class="post-metadata">

**Author:** ![HaroldPetersInskipp](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/haroldpetersinskipp/32/42319_2.png) [@HaroldPetersInskipp](https://discourse.nodered.org/u/HaroldPetersInskipp)\
**Post date:** [30 June 2022 17:22 UTC](https://discourse.nodered.org/t/function-crashing-node-red-fatal-javascript-invalid-size-error/64549/8 "2022-06-30T17:22:17Z")

</div>

Thank you so much!

```auto
msg.payload = false; //assume failure

for (let index = 0; index < 50; index++) {
    const inBox = boxes[boxToCheck]
    if (inBox === prisonerNo) {
        msg.payload = true
        break
    }
    boxToCheck = inBox;
}

```

This part of your code was what I needed to figure out.

I really like knowing this from your code too:

```auto
msg.payload = [null, ...shuffle(emptyBoxes)];

```

Seems like it might make dealing with arrays and off by one math less of a headache.

Excellent advice all around, I truly appreciate the help from you all.

---

<div class="post-metadata">

**Author:** ![HaroldPetersInskipp](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/haroldpetersinskipp/32/42319_2.png) [@HaroldPetersInskipp](https://discourse.nodered.org/u/HaroldPetersInskipp)\
**Post date:** [30 June 2022 19:15 UTC](https://discourse.nodered.org/t/function-crashing-node-red-fatal-javascript-invalid-size-error/64549/9 "2022-06-30T19:15:24Z")

</div>

Is there a way to set say `msg.payload.loops` to an array of each unique loop?

---

<div class="post-metadata">

**Author:** ![Steve-Mcl](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/steve-mcl/32/4826_2.png) [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)\
**Post date:** [30 June 2022 19:27 UTC](https://discourse.nodered.org/t/function-crashing-node-red-fatal-javascript-invalid-size-error/64549/10 "2022-06-30T19:27:34Z")

</div>

i dont follow. What are you trying to achieve? Do you want to keep multiple set of results? Or do you just want the final result in a certain format?

---

<div class="post-metadata">

**Author:** ![HaroldPetersInskipp](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/haroldpetersinskipp/32/42319_2.png) [@HaroldPetersInskipp](https://discourse.nodered.org/u/HaroldPetersInskipp)\
**Post date:** [30 June 2022 19:41 UTC](https://discourse.nodered.org/t/function-crashing-node-red-fatal-javascript-invalid-size-error/64549/11 "2022-06-30T19:41:03Z")

</div>

My goal is in analyzing probabilities of each the loop sizes over multiple runs. As it is currently any time the flow results in freedom then we can conclude no loops exceed 50 in length.

---

<div class="post-metadata">

**Author:** ![Steve-Mcl](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/steve-mcl/32/4826_2.png) [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)\
**Post date:** [30 June 2022 19:56 UTC](https://discourse.nodered.org/t/function-crashing-node-red-fatal-javascript-invalid-size-error/64549/12 "2022-06-30T19:56:19Z")

</div>

So you want to gather the min/max number of box openings over multiple runs? Something else. Please be specific.

---

<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)\
**Post date:** [14 July 2022 19:56 UTC](https://discourse.nodered.org/t/function-crashing-node-red-fatal-javascript-invalid-size-error/64549/13 "2022-07-14T19:56:32Z")

</div>

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