Utility: Snake_case to camelCase HTTP interceptor

[benjamincharity]

Core currently has:

import { Injectable } from '@angular/core';
import {
  HttpRequest,
  HttpResponse,
  HttpHandler,
  HttpEvent,
  HttpInterceptor,
} from '@angular/common/http';
import { Observable } from 'rxjs/Observable';
declare function require(name: string): any;

@Injectable()
export class CamelCaseInterceptor implements HttpInterceptor {

  intercept(request: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
    const camelcaseKeys = require('camelcase-keys');
    return next.handle(request)
      .map((event: HttpEvent<any>) => {
        if (
          event instanceof HttpResponse &&
          (event.headers.get('content-type') || '').indexOf('application/json') > - 1
          && event.body.constructor !== Array
        ) {
          // TODO: Temporarily leaving in both snakecase and adding camelcase keys until all of app is updated
          return event.clone({
            body: Object.assign(
              {},
              event.body,
              camelcaseKeys(event.body, { deep: true, exclude: ['_permissions'] }),
            ),
          });
        }
        return event;
      });
  }
}