Node.js crashing during Angular 6 build with --watch

I am using Node v8.12.0 on Mac (although I've seen this issue with Node 9.x versions, and also on Linux).

I am developing Angular 6 app, and am running dev builds with --watch flag. The watch will run and can rebuild the app maybe 4 or 5 times, then Node crashes with the following output:

<--- Last few GCs --->

[34201:0x104000000]   273927 ms: Mark-sweep 1309.4 (1430.5) -> 1309.2 (1431.0) MB, 1296.0 / 0.0 ms  allocation failure GC in old space requested
[34201:0x104000000]   275358 ms: Mark-sweep 1309.2 (1431.0) -> 1309.2 (1424.0) MB, 1430.8 / 0.0 ms  last resort GC in old space requested
[34201:0x104000000]   276946 ms: Mark-sweep 1309.2 (1424.0) -> 1309.2 (1423.5) MB, 1587.7 / 0.0 ms  last resort GC in old space requested


<--- JS stacktrace --->

==== JS stack trace =========================================

Security context: 0x1c5f3a825879 <JSObject>
1: fromString(aka fromString) [buffer.js:~298] [pc=0x2234a1ca140b](this=0x1c5ffcc022d1 <undefined>,string=0x1c5f6f8dffa1 <Very long string[784654]>,encoding=0x1c5ffcc022d1 <undefined>)
2: from [buffer.js:177] [bytecode=0x1c5f43e4aac9 offset=11](this=0x1c5f8a5b5c51 <JSFunction Buffer (sfi = 0x1c5f3a87e159)>,value=0x1c5f6f8dffa1 <Very long string[784654]>,encodingOrOffset=0x1c5ffcc022d1 <u...

FATAL ERROR: CALL_AND_RETRY_LAST Allocation failed - JavaScript heap out of memory
 1: node::Abort() [/usr/local/bin/node]
 2: node::FatalException(v8::Isolate*, v8::Local<v8::Value>, v8::Local<v8::Message>) [/usr/local/bin/node]
 3: v8::internal::V8::FatalProcessOutOfMemory(char const*, bool) [/usr/local/bin/node]
 4: v8::internal::Factory::NewRawTwoByteString(int, v8::internal::PretenureFlag) [/usr/local/bin/node]
 5: v8::internal::String::SlowFlatten(v8::internal::Handle<v8::internal::ConsString>, v8::internal::PretenureFlag) [/usr/local/bin/node]
 6: v8::String::WriteUtf8(char*, int, int*, int) const [/usr/local/bin/node]
 7: node::StringBytes::Write(v8::Isolate*, char*, unsigned long, v8::Local<v8::Value>, node::encoding, int*) [/usr/local/bin/node]
 8: node::Buffer::New(v8::Isolate*, v8::Local<v8::String>, node::encoding) [/usr/local/bin/node]
 9: node::Buffer::(anonymous namespace)::CreateFromString(v8::FunctionCallbackInfo<v8::Value> const&) [/usr/local/bin/node]
10: 0x2234a02d4067
11: 0x2234a1ca140b
12: 0x2234a023d1d6
13: 0x2234a018535f

I have tried adding --max_old_space_size=12000 also, but it has not seemed to make any difference. I'm not sure where to look for the cause of the issue, or how to even begin debugging in Node. Any assistance would be hugely appreciated!

Some background: it was Angular 5 app with ejected config, and I have updated it to Angular 6, with the same config, and the app itself is working as expected. It is only since updating to Angular 6 that this issue started to arise.

from Node.js crashing during Angular 6 build with --watch