title: angular library install peer dependency problem
body: <p>Every time I am trying to install an angular library using npm (for example I need this library: <a href="https://www.npmjs.com/package/ngx-pinch-zoom" rel="nofollow noreferrer">https://www.npmjs.com/package/ngx-pinch-zoom</a> ), I get a couple of warnings saying that I should install peer dependencies myself.</p>
  
  <pre><code> npm WARN @progress/kendo-theme-bootstrap@2.6.2 requires a peer of bootstrap@git://github.com/twbs/bootstrap.git#95f37e4c402df37db16781995ffa1592032df9c8 but none is installed. You must install peer dependencies yourself.
      npm WARN ngx-pinch-zoom@1.2.0 requires a peer of @angular/common@^6.0.0-rc.0 || ^6.0.0 but none is installed. You must install peer dependencies yourself.
      npm WARN ngx-pinch-zoom@1.2.0 requires a peer of @angular/core@^6.0.0-rc.0 || ^6.0.0 but none is installed. You must install peer dependencies yourself.
      npm WARN optional SKIPPING OPTIONAL DEPENDENCY: fsevents@1.1.3 (node_modules\fsevents):
      npm WARN notsup SKIPPING OPTIONAL DEPENDENCY: Unsupported platform for fsevents@1.1.3: wanted {"os":"darwin","arch":"any"} (current: {"os":"win32","arch":"x64"})
  </code></pre>
  
  <p>I have tried to downgrade the npm to a version less than 3, but I get the same thing:
      npm install npm@2.8.4</p>
  
  <pre><code>Testing binary
  Binary is fine
  npm WARN @progress/kendo-theme-bootstrap@2.6.2 requires a peer of bootstrap@git://github.com/twbs/bootstrap.git#95f37e4c402df37db16781995ffa1592032df9c8 but none is installed. You must install peer dependencies yourself.
  npm WARN optional SKIPPING OPTIONAL DEPENDENCY: fsevents@1.1.3 (node_modules\fsevents):
  npm WARN notsup SKIPPING OPTIONAL DEPENDENCY: Unsupported platform for fsevents@1.1.3: wanted {"os":"darwin","arch":"any"} (current: {"os":"win32","arch":"x64"})
  
  + npm@2.8.4
  added 469 packages from 498 contributors, removed 230 packages, updated 29 packages and audited 5980 packages in 62.539s
  found 226 vulnerabilities (66 low, 106 moderate, 51 high, 3 critical)
    run `npm audit fix` to fix them, or `npm audit` for details
  </code></pre>
  
  <blockquote>
    <p>npm -v
        6.5.0</p>
  </blockquote>
  
  <p>And after that, the version is still 6.5.0. What could be the solution? </p>