SPFx 1.22 Project Crashing with 'JavaScript heap out of memory'

[HiltonGiesenow]

Target SharePoint environment

SharePoint Online

What SharePoint development model, framework, SDK or API is this about?

💥 SharePoint Framework

Developer environment

Windows

What browser(s) / client(s) have you tested

• 💥 Internet Explorer
• 💥 Microsoft Edge
• 💥 Google Chrome
• 💥 FireFox
• 💥 Safari
• mobile (iOS/iPadOS)
• mobile (Android)
• not applicable
• other (enter in the "Additional environment details" area below)

Additional environment details

• browser version: Version 147.0.7727.56 (Official Build) (64-bit)
• SPFx version: 1.22
• Node.js version: 22.2

Describe the bug / error

I have a fairly chunky SPFx 'intranet' project, with 32 webparts and a custom header+footer, and I've recently upgraded it from SPFx 1.21 to 1.22. It's now crashing regularly when debugging locally (npm run start to launch Heft).

I can browse the page and make code changes maybe once or twice, then it dies with the following:

Starting incremental build...
---- build started ----
[build:set-browserslist-ignore-old-data-env-var] Setting environment variable BROWSERSLIST_IGNORE_OLD_DATA=1
[build:webpack] Running incremental Webpack compilation

<--- Last few GCs --->

[126132:0000025ABF80E000] 563169 ms: Mark-Compact 4088.7 (4138.0) -> 4085.7 (4139.0) MB, pooled: 2 MB, 635.84 / 0.00 ms (average mu = 0.117, current mu = 0.006) allocation failure; scavenge might not succeed
[126132:0000025ABF80E000] 564477 ms: Mark-Compact 4089.6 (4139.0) -> 4086.6 (4139.8) MB, pooled: 1 MB, 1302.52 / 0.00 ms (average mu = 0.043, current mu = 0.004) allocation failure; scavenge might not succeed

<--- JS stacktrace --->

FATAL ERROR: Reached heap limit Allocation failed - JavaScript heap out of memory
----- Native stack trace -----

1: 00007FF76C4818E7 node::SetCppgcReference+18263
2: 00007FF76C3E212B v8::base::CPU::num_virtual_address_bits+103083
3: 00007FF76CFEAE51 v8::Isolate::ReportExternalAllocationLimitReached+65
4: 00007FF76CFD7916 v8::Function::Experimental_IsNopFunction+3302
5: 00007FF76CE34060 v8::internal::StrongRootAllocatorBase::StrongRootAllocatorBase+33904
6: 00007FF76CE306EA v8::internal::StrongRootAllocatorBase::StrongRootAllocatorBase+19194
7: 00007FF76CE46CCC v8::Isolate::GetHeapProfiler+8012
8: 00007FF76CE4754A v8::Isolate::GetHeapProfiler+10186
9: 00007FF76CE57F3B v8::Isolate::GetHeapProfiler+78267
10: 00007FF76CB2503B v8::base::AddressSpaceReservation::AddressSpaceReservation+323419
11: 00007FF70D06D8D0

Steps to reproduce

1. Run project with npm run start
2. Load page in SPO with appropriate querystring from cmdline (?debugManifestsFile=...)
3. Make a code change, and the process terminates with error per above (might need two or three changes).

Expected behavior

Process should not terminate

[Ashlesha-MSFT]

Hello @HiltonGiesenow,
Thank you for bringing this issue to our attention. We will look into it and get back to you shortly.
If you don’t receive a reply within two working days, please use this escalation form to escalate.

[Ashlesha-MSFT]

@HiltonGiesenow,
This behavior is consistent with a previously reported scenario in the SPFx repository: #7959

In that case, similar memory issues were observed when moving between Node.js versions. The SPFx team indicated that newer Node versions may not always work optimally with the existing build tooling (Webpack/Heft), particularly for larger solutions. The issue was mitigated by increasing the Node.js heap size rather than a product fix.

Given the similarities (large solution, incremental build failures, heap exhaustion), we recommend the following:

1. Increase Node.js heap size (recommended workaround)

set NODE_OPTIONS=--max-old-space-size=8192
npm run start

2. Validate against a supported Node.js version
Please test with Node.js 18 LTS (or 20 LTS if applicable), as Node.js 22 may not yet be fully supported with SPFx 1.22.

3. Confirm behavior

• If the issue is resolved with increased heap size → indicates memory pressure during build
• If the issue does not reproduce on Node 18/20 → likely compatibility-related rather than a product defect

If the problem persists even on a supported Node version with increased memory, please let us know and we can investigate further as a potential bug.

[HiltonGiesenow]

Thanks @Ashlesha-MSFT , I'll try that. I forget to mention, importantly, that I needed to set --max-old-space-size=8192 when doing the gulp bundle on this project, so the fix should probably work - I'll try it and revert.

Incidentally, Node.js 22 is listed -as- the supported version over here: https://learn.microsoft.com/en-us/sharepoint/dev/spfx/set-up-your-development-environment#install-nodejs

[HiltonGiesenow]

Nope, it's not working unfortunately.

[andrewconnell]

@Ashlesha-MSFT said:

Please test with Node.js 18 LTS (or 20 LTS if applicable), as Node.js 22 may not yet be fully supported with SPFx 1.22.

That's not correct...

SPFx v1.21.* & v1.22.* only support Node.js v22. The SPFx v1.21 shipped only supporting Node v22 and that's still true in SPFx v1.22.