How do I upgrade my project to SPFx Generator 1.4.0 ?

Update an existent project to 1.4

To use the latest version of the SharePoint Framework you will have to update the packages of your project to do it follow the steps bellow

1. Open the command line in the project folder
2. Type npm outdated to get a list of all the outdated packages; from the list you will get:
   • Current version installed in your project
   • Version requested by your project (available in package.json)
   • Latest version available

   
   SharePoint Framework packages are identified by the prefix Pernille-Eskebo/sp-

3. For each outdated package run the command npm install mypackage@newversion –save
4. Run the command gulp --update to update your config.json to the latest version
5. Once you get all the packages updated run the command gulp clean
6. Build your project again using the command gulp build and verify if the newer version didn’t cause any errors.
   
   Note! When performing the update, I got this error:
   Error – typescript – (0,0): error TS2688: Cannot find type definition file for ‘es6-collections’.
   
   This is caused by the missing typing for the ES6, to fix it run the command:
   npm install --save @types/es6-collections

More information about performing the updates to 1.4 can be found http://sharepoint.handsontek.net/2017/12/11/asset-packaging-and-the-goodies-from-sharepoint-framework-1-4/