Out-of-memory compiling project that uses fp-ts 0.2.6+ and TS@next

[sandersn]

@OliverJAsh kindly provided a small repro:

This fixed the issue for https://github.com/OliverJAsh/ts-2.4-memory-issue, but I ran into another scenario where the memory issue pops up again. I've created a small test case in https://github.com/OliverJAsh/ts-2.4-memory-issue/tree/2.4.0-dev.20170519.

@sledorze additionally noted that the issue happens with ill-typed programs, not well-typed ones.

[OliverJAsh]

Thanks for opening this!

[sledorze]

Thanks a lot!!!!

[OliverJAsh]

@sandersn Do you have any tips about how to debug this in a TypeScript application? I'm currently blocked by it :-(

[OliverJAsh]

I was able to fix the issue in my example project by deduping fp-ts so there was only one version, not two. The example uses 0.2.8 and 0.2.7. However this was not easy to find, so ideally tsc would tell me the error still.

[gillesfabre34]

Hello,
I have the same bug in this situation :

In a first component, I have a field like this :

this.foreignFields = [{objectType: 'Region'}, {objectType: 'Item'}];

This component extends an abstract class where the type of this.foreignFields is defined like this :

foreignFields: [{objectType:any}];

In this configuration, I can have two kinds of problems :

• very long time to compile
• a bug during compilation with this message :

FATAL ERROR: CALL_AND_RETRY_LAST Allocation failed - JavaScript heap out of memory

But if I remove one object from my array, like this :

this.foreignFields = [{objectType: 'Region'}];

there is no bug.

I can "fix" this bug with two other ways :

• Instead of writing in abstract class

foreignFields: [{objectType:any}];

I write

foreignFields: any;

• Instead of declaring type in abstract class, I declare it inside my concrete component

Hope it will helps.

[gillesfabre34]

Other "solution" :

Instead of declaring type in my abstract class like this :

foreignFields: [{objectType:any}];

I do :

foreignFields: ForeignFields;

and I declare my new type ForeignFields :

export type ForeignFields = [{objectType: any}];

[sandersn]

@gillesfabre34 are you using fp-ts as well? Or is your repro standalone?

I think you also meant to have foreignFields: { objectType: any }[]. Infix brackets means a unary one-element tuple in TypeScript. Postfix brackets means array.

If that is correct, hopefully that is an even better workaround.

[gillesfabre34]

No, I don't use fp-ts, but I had the same error message with my own webapp.

I searched help on Google and I found your issue which seems to be the same than mine, but maybe not. So I thought it could help you to see another situation with the same problem.

About using Array or Tuple, in fact I wanted to have an array where each element was of type {objectType: any}. But maybe that I needed to declare at first my type ForeignFields = [{objectType: any}]. In fact, maybe that typescript didn't really understand that I was using my own type in my array.

Changing foreignFields: [{objectType:any}] by foreignFields: { objectType: any }[] solved the problem as well as exporting a new type ForeignFields = [{objectType: any}];, so thanks for your help.

I hope that my bug will help you to solve yours ...

[OliverJAsh]

I have a project that has no compile errors and all dependencies share the same version of fp-ts. If I try updating one of these dependencies to use a different fp-ts version, the memory issue reappears. Perhaps there are compile errors from the upgrade being masked by the memory issue.

[OliverJAsh]

I can also confirm this error still occurs with TypeScript 2.4.2.

[sandersn]

#17984 fixes this. It finishes in 2.3 seconds after #17984, 4.2 seconds on 2.3 and crashes out-of-memory before #17984.