# Solution for Angular NgClass Import Error

## Issue Description

When running `npm start` in the airwatch directory, the following error occurred:

```
✘ [ERROR] NG3004: Unable to import symbol NgClass.
  The symbol is not exported from /home/poule/encrypted/stockage-syncable/www/development/html/ng-implementation/airwatch/node_modules/@angular/common/index.d.ts (module '@angular/common'). [plugin angular-compiler]

    ../my-workspace/projects/sae-lib/buttons/main-button/main-button.ngtypecheck.ts:0:0:
      0 │ 
        ╵ ^

  The symbol is declared here.

    ../my-workspace/projects/sae-lib/node_modules/@angular/common/common_module.d.d.ts:351:0:
      351 │ declare class NgClass implements DoCheck {
          ╵ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
```

## Root Cause

The error occurred because:

1. The `main-button` component in the `sae-lib` project was importing `NgClass` directly from `@angular/common`.
2. In Angular 20+ (the project is using Angular 20.1.0), `NgClass` is no longer exported directly from `@angular/common` but is available from `@angular/common/directives`.
3. Additionally, the `link-sae-lib.sh` script was incorrectly linking `sae-lib` to `old-sae-airwatch` instead of the `airwatch` project.

## Changes Made

1. Updated the import statement in `/my-workspace/projects/sae-lib/buttons/main-button/main-button.ts`:
   ```typescript
   // Changed from:
   import {NgClass} from '@angular/common';
   
   // To:
   import {NgClass} from '@angular/common/directives';
   ```

2. Fixed the `link-sae-lib.sh` script to link `sae-lib` to the `airwatch` project instead of `old-sae-airwatch`:
   ```bash
   # Changed from:
   cd ../../../old-sae-airwatch
   echo "Utilisation du lien dans l'application old-sae-airwatch..."
   
   # To:
   cd ../../../airwatch
   echo "Utilisation du lien dans l'application airwatch..."
   ```

## Additional Requirements

When attempting to verify the fix, a Node.js version compatibility issue was discovered:

```
Node.js version v20.18.1 detected.
The Angular CLI requires a minimum Node.js version of v20.19 or v22.12.
```

To fully run the application, you'll need to update Node.js to version v20.19+ or v22.12+.

## How to Update Node.js

You can update Node.js using one of the following methods:

### Using NVM (Node Version Manager)
```bash
# Install NVM if not already installed
curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.39.7/install.sh | bash

# Install and use the required Node.js version
nvm install 20.19
nvm use 20.19
```

### Using the Official Node.js Installer
1. Visit https://nodejs.org/
2. Download and install version 20.19 or higher

After updating Node.js, run `npm start` in the airwatch directory to verify that both the NgClass import issue and the Node.js version issue are resolved.