title: How to add @angular/material to an old angular project?
body: <p>I installed <em><strong>@angular/material</strong></em> using  <code>npm i @angular/material</code>  but every time i start angular app using  <code>npm start</code>  it throws below error:</p>
  <pre><code>node_modules/@angular/material/index.d.ts' is not a module
  </code></pre>
  <p>slice of my package.json:</p>
  <pre><code>  &quot;devDependencies&quot;: {
      &quot;@angular-devkit/build-angular&quot;: &quot;~0.803.4&quot;,
      &quot;@angular/cli&quot;: &quot;~8.3.4&quot;,
      &quot;@angular/compiler-cli&quot;: &quot;~8.2.5&quot;,
      &quot;@angular/language-service&quot;: &quot;~8.2.5&quot;,
      &quot;@types/node&quot;: &quot;~8.9.4&quot;,
  </code></pre>
  <p>I tried different versions of angular-material but still getting same error.</p>