How to init Google Cloud Storage NodeJS client library with service account credentials

So I have the service account credentials json (as a string, or json object in my code):

{
  "type": "service_account",
  "project_id": "myproject",
  "private_key_id": "lkjshdjhskas",
  //.... etc
}

and then I have this simple Cloud Storage upload snippet:

const {Storage} = require('@google-cloud/storage');

const creds = {service_account_object:"creds are here"};

const storage = new Storage();

const bucketName = 'my-bucket';
const filename = 'my-file.txt';

storage.bucket(bucketName).upload(filename, {
  gzip: true,
  metadata: {
    cacheControl: 'public, max-age=31536000',
  },
});

This is gives me an invalid_grant error, of course:

(node:15920) UnhandledPromiseRejectionWarning: Error: invalid_grant
    at Gaxios.request (C:\Users\Yuri\Documents\Code\btests\node_modules\gaxios\build\src\gaxios.js:70:23)
    at process._tickCallback (internal/process/next_tick.js:68:7)
(node:15920) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 1)
(node:15920) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

I tried providing the creds as a param to the Storage() constructor, lie this Storage(creds) or even Storage(JSON.stringify(creds)) but it just gives me weird errors.

How do instantiate a Google client library object with service account credentials?

The credentials data should be passed in the credentials property of the StorageOptions object that you pass to the constructor:

const creds = {
  "type": "service_account",
  "project_id": "myproject",
  "private_key_id": "lkjshdjhskas",
  //.... etc
}

const storage = new Storage({
  credentials: creds
});

Definitely familiarize yourself with the linked API docs, as they will explain how to use the APIs.