Auto-downgrading all dependencies in Node - node.js

Question

Bit of a noobish question here, I'm currently working on a project in angular. But I was wondering if it were possible to downgrade all the dependencies in that project so they're all compatible with each other. I'm currently using Angular Core 5.2.0 but it would appear that there is no version of 'ngx-signalr-hubservice' that is compatible with that angular version, it needs angular core 4.3.2... Here's what's in my packages.json:
"dependencies": {
"#angular/animations": "^5.2.0",
"#angular/cdk": "^5.2.0",
"#angular/common": "^5.2.0",
"#angular/compiler": "^5.2.0",
"#angular/core": "^5.2.0",
"#angular/forms": "^5.2.0",
"#angular/http": "^5.2.0",
"#angular/material": "^5.2.0",
"#angular/platform-browser": "^5.2.0",
"#angular/platform-browser-dynamic": "^5.2.0",
"#angular/router": "^5.2.0",
"angular-confirm": "^2.0.0-alpha.2",
"core-js": "^2.4.1",
"hammerjs": "^2.0.8",
"jquery": "^3.3.1",
"ng-drag-drop": "^4.0.1",
"ng2-signalr": "^5.0.0",
"rxjs": "^5.5.6",
"signalr": "^2.2.3",
"zone.js": "^0.8.19"
},
"devDependencies": {
"#angular/cli": "~6.0.8",
"#angular/compiler-cli": "^5.2.0",
"#angular/language-service": "^5.2.0",
"#types/jasmine": "~2.8.3",
"#types/jasminewd2": "~2.0.2",
"#types/node": "~6.0.60",
"codelyzer": "^4.0.1",
"jasmine-core": "~2.8.0",
"jasmine-spec-reporter": "~4.2.1",
"karma": "~2.0.0",
"karma-chrome-launcher": "~2.2.0",
"karma-coverage-istanbul-reporter": "^1.2.1",
"karma-jasmine": "~1.1.0",
"karma-jasmine-html-reporter": "^0.2.2",
"protractor": "~5.1.2",
"ngx-signalr-hubservice": "^2.0.7", <- This one is incompatible
"ts-node": "~4.1.0",
"tslint": "~5.9.1",
"typescript": "~2.5.3",
"#angular-devkit/build-angular": "~0.6.8"
}
So... What's the best way to approach this? Also, this is my very first StackOverflow post, have mercy on me please ;)

Answer 1

There are lots of tools and helpful options for moving forward versions ... I don't know of any way to easily move backward.
You can do: npm install #angular/core#4.3.2
But you'd have to know exactly which version of each library you'd need.
You could try to install the older version of the Angular CLI and use it to generate a package.json file for you. Then you would know the right set of libraries you'd need to install.
I think that it was 'npm install -g #angular/cli#1.2.4` that was compatible with Angular 4.x.