title: Gulp 4 TypeScript Compilation Errors
body: <p>I am using Gulp 4 and compiling Typescript down to javascript. For this i am using the gulp-typescript plugin. Although it does compile i recieve a bunch of errors while compliling:</p>
  
  <p>Errors:</p>
  
  <pre><code>[17:43:02] Using gulpfile ~/Sites/dmfa/gulpfile.js
  [17:43:02] Starting 'typescript'...
  [17:43:02] Starting 'clean-typescript'...
  [17:43:02] Cleaning: ./web/js/**/*.js
  [17:43:02] Finished 'clean-typescript' after 21 ms
  [17:43:02] Starting '&lt;anonymous&gt;'...
  [17:43:02] Compiling TypeScript --&gt; JavaScript
  error TS2304: Cannot find name 'Promise'.
  error TS2304: Cannot find name 'Map'.
  error TS2304: Cannot find name 'MapConstructor'.
  error TS2304: Cannot find name 'SetConstructor'.
  error TS2304: Cannot find name 'Set'.
  error TS2304: Cannot find name 'Iterator'.
  [17:43:03] TypeScript: 76 semantic errors
  [17:43:03] TypeScript: emit succeeded (with errors)
  [17:43:03] Finished '&lt;anonymous&gt;' after 1.75 s
  [17:43:03] Finished 'typescript' after 1.77 s
  
  Process finished with exit code 0
  </code></pre>
  
  <p>Although this still compiles real errors maybe be over looked and it would be more pleasing to me to correct the errors. </p>
  
  <p>Can anyone give me some insight into why these errors happen.</p>