title: Adding bootstrap to angular 12.1.4 - unable to resolve dependency tree
body: <p>I am trying to install bootstrap in a new angular app but it doesn't work</p>
  <pre><code>ng add @ng-bootstrap/ng-bootstrap
  </code></pre>
  <p>I get this error below, what do I need to do to fix this?</p>
  <pre><code>The package @ng-bootstrap/ng-bootstrap@10.0.0 will be installed and executed.  
  Would you like to proceed? Yes
  npm ERR! code ERESOLVE
  npm ERR! ERESOLVE unable to resolve dependency tree
  npm ERR!
  npm ERR! While resolving: how-to-test@0.0.0
  npm ERR! Found: @angular/compiler@12.1.5
  npm ERR! node_modules/@angular/compiler
  npm ERR!   @angular/compiler@&quot;~12.1.0&quot; from the root project
  npm ERR!
  npm ERR! Could not resolve dependency:
  npm ERR! peer @angular/compiler@&quot;12.2.0&quot; from @angular/localize@12.2.0
  npm ERR! node_modules/@angular/localize
  npm ERR!   peer @angular/localize@&quot;^12.0.0&quot; from @ng-bootstrap/ng-bootstrap@10.0.0
  npm ERR!   node_modules/@ng-bootstrap/ng-bootstrap
  npm ERR!     @ng-bootstrap/ng-bootstrap@&quot;10.0.0&quot; from the root project
  npm ERR!
  npm ERR! Fix the upstream dependency conflict, or retry
  npm ERR! this command with --force, or --legacy-peer-deps
  npm ERR! to accept an incorrect (and potentially broken) dependency resolution.npm ERR!
  npm ERR! See C:\Users\Andrew\AppData\Local\npm-cache\eresolve-report.txt for a 
  full report.
  
  npm ERR! A complete log of this run can be found in:
  npm ERR!     C:\Users\Andrew\AppData\Local\npm-cache\_logs\2021-08-04T19_50_44_840Z-debug.log
  ✖ Package install failed, see above.
  </code></pre>
  <p>my angular version details are as follows</p>
  <pre><code>Angular CLI: 12.1.4
  Node: 15.8.0 (Unsupported)
  Package Manager: npm 7.20.3
  OS: win32 x64
  
  Angular: 12.1.5
  ... animations, common, compiler, compiler-cli, core, forms
  ... platform-browser, platform-browser-dynamic, router
  
  Package                         Version
  ---------------------------------------------------------
  @angular-devkit/architect       0.1201.4
  @angular-devkit/build-angular   12.1.4
  @angular-devkit/core            12.1.4
  @angular-devkit/schematics      12.1.4
  @angular/cli                    12.1.4
  @schematics/angular             12.1.4
  rxjs                            6.6.7
  typescript                      4.3.5
  </code></pre>
  <p>Can anyone help with a good answer? as all of this seems to work one day they doesn't the next.</p>
  <p><strong>Update 05/08/2021</strong></p>
  <p>I still cant get it working, I tried these steps.</p>
  <pre><code>npm uninstall -g @angular/cli
  npm install -g @angular/cli@12.0.0
  </code></pre>
  <p>I uninstalled and re-installed node.js as well, version 14.17.4</p>
  <pre><code>npm uninstall --save-dev @angular/cli
  npm install --save-dev @angular/cli@12.0.0
  
  npm install
  </code></pre>
  <p>running</p>
  <pre><code>ng version
  </code></pre>
  <p>give me this:</p>
  <pre><code>Angular CLI: 12.2.0
  Node: 14.17.4
  Package Manager: npm 7.20.3
  OS: win32 x64
  
  Angular: 12.0.5
  ... animations, common, compiler, compiler-cli, core, forms
  ... platform-browser, platform-browser-dynamic, router
  
  Package                         Version
  ---------------------------------------------------------
  @angular-devkit/architect       0.1200.5
  @angular-devkit/build-angular   12.0.5
  @angular-devkit/core            12.0.5
  @angular-devkit/schematics      12.2.0
  @angular/cli                    12.2.0
  @schematics/angular             12.2.0
  rxjs                            6.6.7
  typescript                      4.2.4
  </code></pre>
  <p>Then again when I run this</p>
  <pre><code>ng add @ng-bootstrap/ng-bootstrap
  </code></pre>
  <p>I get a similar issue with the @angular/compiler.
  This is located in the <strong>package-lock.json</strong> file. Why does it say 12.0.5 when I installed 12.0.0. (ruddy confusing)?</p>
  <pre><code>The package @ng-bootstrap/ng-bootstrap@10.0.0 will be installed and executed.
  Would you like to proceed? Yes
  npm ERR! code ERESOLVE
  npm ERR! ERESOLVE unable to resolve dependency tree
  npm ERR!
  npm ERR! While resolving: how-to-test@0.0.0
  npm ERR! Found: @angular/compiler@12.0.5
  npm ERR! node_modules/@angular/compiler
  npm ERR!   @angular/compiler@&quot;~12.0.0&quot; from the root project
  npm ERR!
  npm ERR! Could not resolve dependency:
  npm ERR! peer @angular/compiler@&quot;12.2.0&quot; from @angular/localize@12.2.0
  npm ERR! node_modules/@angular/localize
  npm ERR!   peer @angular/localize@&quot;^12.0.0&quot; from @ng-bootstrap/ng-bootstrap@10.0.0
  npm ERR!   node_modules/@ng-bootstrap/ng-bootstrap
  npm ERR!     @ng-bootstrap/ng-bootstrap@&quot;10.0.0&quot; from the root project
  npm ERR!
  npm ERR! Fix the upstream dependency conflict, or retry
  npm ERR! this command with --force, or --legacy-peer-deps
  npm ERR! to accept an incorrect (and potentially broken) dependency resolution.
  npm ERR!
  </code></pre>