WebStorm, An async function or method in ES5/ES3 requires the 'Promise' constructor

Adding

"lib": [ "es2015" ]

to tsconfig.json should fix the issue. However it seems that your spec files are not included in your tsconfig.json (check "include":[] and "exclude":[] values). So the Typescript service must be using a different tsconfig.json for your files (may be a default one, if no tsconfig.json files that include your specs can be found) To fix the issue, make sure to specify the lib property in config that is used for your spec files processing

Solution without editing the project sources

I had this problem with IntelliJ and resolved by changing my IDE settings:

Settings -> Language & Frameworks -> TypeScript

then in the "Options" field add:

--lib es2015