title: this.map.set(key,value) function is not working in angualr 6 typescript 2.9.2
body: <p>I have a map(<code>this.mymap</code>) of type <code>Map&lt;string, Person[]&gt;</code> where <code>Person</code>is a class and addEntry() function. But it is giving me an error below when I try to set the entry in <code>this.mymap</code> variable.</p>
  <blockquote>
  <p>this.mymap.set is not function</p>
  </blockquote>
  <p><strong>component.ts</strong></p>
  <pre class="lang-js prettyprint-override"><code>    addEntry(value:Person[]){
      Object.keys(this.mymap).forEach(key =&gt; {
                  this.mymap.set(key,value);
                });
      }
  </code></pre>
  <p><strong>package.json</strong></p>
  <pre class="lang-js prettyprint-override"><code>    {
        &quot;name&quot;: &quot;demo-ui&quot;,
        &quot;version&quot;: &quot;0.0.0&quot;,
        &quot;scripts&quot;: {
          &quot;ng&quot;: &quot;ng&quot;,
          &quot;start&quot;: &quot;ng serve --proxy-config proxy.conf.json&quot;,
          &quot;build&quot;: &quot;ng build&quot;,
          &quot;test&quot;: &quot;ng test&quot;,
          &quot;lint&quot;: &quot;ng lint&quot;,
          &quot;e2e&quot;: &quot;ng e2e&quot;
        },
        &quot;private&quot;: true,
        &quot;dependencies&quot;: {
          &quot;@angular/animations&quot;: &quot;6.1.10&quot;,
          &quot;@angular/cdk&quot;: &quot;^6.1.10&quot;,
          &quot;@angular/common&quot;: &quot;^6.1.10&quot;,
          &quot;@angular/compiler&quot;: &quot;^6.1.10&quot;,
          &quot;@angular/core&quot;: &quot;^6.1.10&quot;,
          &quot;@angular/forms&quot;: &quot;^6.1.10&quot;,
          &quot;@angular/http&quot;: &quot;^6.1.10&quot;,
          &quot;@angular/material&quot;: &quot;6.4.7&quot;,
          &quot;@angular/platform-browser&quot;: &quot;^6.1.10&quot;,
          &quot;@angular/platform-browser-dynamic&quot;: &quot;^6.1.10&quot;,
          &quot;@angular/router&quot;: &quot;^6.1.10&quot;,
          &quot;@ng-bootstrap/ng-bootstrap&quot;: &quot;2.1.2&quot;,
          &quot;@types/core-js&quot;: &quot;^2.5.2&quot;,
          &quot;@types/file-saver&quot;: &quot;^2.0.1&quot;,
          &quot;ag-grid-angular&quot;: &quot;^20.2.0&quot;,
          &quot;ag-grid-community&quot;: &quot;^20.2.0&quot;,
          &quot;ag-grid-enterprise&quot;: &quot;^20.2.0&quot;,
          &quot;angular-font-awesome&quot;: &quot;^3.1.2&quot;,
          &quot;angular-notifier&quot;: &quot;^4.1.1&quot;,
          &quot;bootstrap&quot;: &quot;4.1.3&quot;,
          &quot;core-js&quot;: &quot;^2.5.7&quot;,
          &quot;file-saver&quot;: &quot;1.3.8&quot;,
          &quot;font-awesome&quot;: &quot;^4.7.0&quot;,
          &quot;jquery&quot;: &quot;^3.4.0&quot;,
          &quot;lodash&quot;: &quot;4.17.5&quot;,
          &quot;ngx-bootstrap&quot;: &quot;3.0.1&quot;,
          &quot;ngx-spinner&quot;: &quot;^7.1.4&quot;,
          &quot;popper.js&quot;: &quot;^1.15.0&quot;,
          &quot;rxjs&quot;: &quot;^6.3.3&quot;,
          &quot;rxjs-compat&quot;: &quot;^6.3.3&quot;,
          &quot;ts-helpers&quot;: &quot;^1.1.2&quot;,
          &quot;xlsx&quot;: &quot;0.12.13&quot;,
          &quot;zone.js&quot;: &quot;^0.8.20&quot;
        },
        &quot;devDependencies&quot;: {
          &quot;@angular-devkit/build-angular&quot;: &quot;~0.8.0&quot;,
          &quot;@angular/cli&quot;: &quot;^6.2.5&quot;,
          &quot;@angular/compiler-cli&quot;: &quot;6.1.10&quot;,
          &quot;@angular/language-service&quot;: &quot;6.1.10&quot;,
          &quot;@types/jasmine&quot;: &quot;^2.8.9&quot;,
          &quot;@types/lodash&quot;: &quot;4.14.108&quot;,
          &quot;@types/node&quot;: &quot;8.9.4&quot;,
          &quot;jasmine-core&quot;: &quot;2.9.1&quot;,
          &quot;jasmine-spec-reporter&quot;: &quot;4.2.1&quot;,
          &quot;protractor&quot;: &quot;5.3.0&quot;,
          &quot;ts-node&quot;: &quot;4.1.0&quot;,
          &quot;tslint&quot;: &quot;5.9.1&quot;,
          &quot;typescript&quot;: &quot;2.9.2&quot;
        }
      }
  </code></pre>
  <p><strong>tsconfig.json</strong></p>
  <pre class="lang-js prettyprint-override"><code>    {
        &quot;compilerOptions&quot;: {
          &quot;target&quot;: &quot;es5&quot;,
          &quot;module&quot;: &quot;commonjs&quot;,
          &quot;moduleResolution&quot;: &quot;node&quot;,
          &quot;sourceMap&quot;: true,
          &quot;emitDecoratorMetadata&quot;: true,
          &quot;experimentalDecorators&quot;: true,
          &quot;lib&quot;: [ &quot;es2015&quot;, &quot;dom&quot; ],
          &quot;noImplicitAny&quot;: true,
          &quot;suppressImplicitAnyIndexErrors&quot;: true
        }
      }
  </code></pre>
  <p>I need to add an entry in map using map.set function.</p>