jQuery-slimScroll | small jQuery plugin that transforms any div | Plugin library

My guess is that the code is probably running before the page fully loads, try doing

First of all, you have to understand the function of angular.json and package.json.

Angular.json

A file named angular.json at the root level of an Angular workspace provides workspace-wide and project-specific configuration defaults for build and development tools provided by the Angular CLI. Path values given in the configuration are relative to the root workspace folder.

Package.json

Initially, this package.json includes a starter set of packages, some of which are required by Angular and others that support common application scenarios. You add packages to package.json as your application evolves. You may even remove some.

The package.json is organized into two groups of packages:

Dependencies are essential to running applications. DevDependencies are only necessary to develop applications.

So, for the questions of the proper way to add these jquery dependencies, you can do both, the npm install jquery or add to the package.json and if needed to the angular.json.

The difference of both ways is that if you use npm install jquery it will add the dependencies automatically and download the packages to your node_modules, you add it manually, you will need to run npm install anyway, tp get the packages.

Use @import in the style tag to import CSS-files.

@import './assets/plugins/font-awesome/css/font-awesome.min.css'

Also the paths to the files are incorrect, use ./.

./assets/plugins/jquery/jquery-3.1.0.min.js

You are getting invalid Email and password because the variable $email which you are using in your query has no email from the form. After this line:

I guess open() does not return a Promise. Try to add .result like this:

I think the Path of the CSS and JS files need to add / before the link.

Example :

the original path is

you need to add the slash before the link like that :

hope this help you.