GET call, Invalid JSON error when Updating to Angular 9 - json

Question

I am working to update my app to Angular 9 CLI and all of my NPM packages to the latest versions. But when I try to make a GET call to load the data on page load the page breaks with a 400 error returned from the server. This endpoint call breaks:
#Effect()
getAllData$ = this.action$.pipe(
ofType<DataAction>(DATA_ACTION_TYPES.GET_ALL_DATA),
switchMap(() => {
return this.dataservice.getAllData().pipe(
map(data => {
const payload = new DataPayload();
payload.data = data;
return new GottenAllDataAction(data);
})
);
})
);
public getAllData(): Observable<any[]> {
// code hits the dataEndpoint
return this.httpClient
.get(this.dataEndpoint)
.pipe(map(response => plainToClass(DataV2, response as Object[], { groups: ['get'] })));
}
In the network tab I get a 400 error with this response:
Here is the start of my 400 console error from the GET call:
Here is my package.json:
"dependencies": {
"#angular/animations": "9.1.6",
"#angular/cdk": "9.2.3",
"#angular/common": "9.1.6",
"#angular/compiler": "9.1.6",
"#angular/core": "9.1.6",
"#angular/flex-layout": "~9.0.0-beta.29",
"#angular/forms": "9.1.6",
"#angular/material": "9.2.3",
"#angular/platform-browser": "9.1.6",
"#angular/platform-browser-dynamic": "9.1.6",
"#angular/router": "9.1.6",
"#auth0/angular-jwt": "^4.0.0",
"#ngrx/effects": "~9.1.2",
"#ngrx/router-store": "~9.1.2",
"#ngrx/store": "~9.1.2",
"#ngrx/store-devtools": "~9.1.2",
"#nrwl/nx": "6.3.1",
"class-transformer": "0.1.9",
"classlist.js": "^1.1.20150312",
"core-js": "~3.6.5",
"es6-shim": "^0.35.5",
"file-saver": "^2.0.2",
"hammerjs": "2.0.8",
"highcharts": "~8.1.0",
"moment": "~2.25.3",
"ng2-file-upload": "^1.4.0",
"ngx-toastr": "^12.0.1",
"ramda": "^0.27.0",
"reflect-metadata": "~0.1.13",
"rxjs": "~6.5.5",
"rxjs-compat": "~6.5.5",
"tachyons-sass": "^4.9.5",
"tslib": "^1.11.2",
"typedjson": "^1.5.1",
"zone.js": "~0.10.3"
},
"devDependencies": {
"#angular-devkit/build-angular": "~0.901.5",
"#angular-devkit/core": "9.1.5",
"#angular-devkit/schematics": "9.1.5",
"#angular/cli": "9.1.5",
"#angular/compiler-cli": "9.1.6",
"#angular/language-service": "9.1.6",
"#nrwl/schematics": "8.12.11",
"#schematics/angular": "9.1.3",
"#types/highcharts": "5.0.4",
"#types/jasmine": "^3.5.10",
"#types/jasminewd2": "~2.0.8",
"#types/node": "^13.13.4",
"codelyzer": "^5.2.2",
"fibers": "^3.1.0",
"html-webpack-plugin": "^4.2.1",
"jasmine-core": "^3.5.0",
"jasmine-marbles": "0.3.1",
"jasmine-spec-reporter": "^5.0.2",
"karma": "~5.0.5",
"karma-chrome-launcher": "^3.1.0",
"karma-cli": "^2.0.0",
"karma-coverage-istanbul-reporter": "^3.0.2",
"karma-jasmine": "^3.1.1",
"karma-jasmine-html-reporter": "^1.5.3",
"ng-mocks": "^9.3.0",
"node-sass": "^4.14.0",
"prettier": "^1.18.2",
"protractor": "^5.4.4",
"remote-redux-devtools": "^0.5.16",
"ts-node": "~8.10.1",
"tslint": "~6.1.2",
"typescript": "~3.8.3"
}
Everything works fine in Angular 8. This error only occurs on my current branch where I am trying to update to the latest Angular 9. But I'm not sure how a front end issue could be causing the error I'm seeing. Could this be a problem with one of the NPM package updates?
Any help is appreciated.

Answer 1

Try these steps:
Delete node-modules folder C:\Users\USER\AppData\Roaming\npm\node_modules
Open windows powershell as admin
npm cache clean --force
npm install -g npm#latest
npm uninstall -g angular-cli
npm install -g #angular/cli#latest