Use async functions wherever applicable

[raphinesse]

Using the async keyword ensures that a function will always return a Promise. Previously this was achieved by wrapping the function body in return Promise.resolve().then(…) which has a very slight async penalty and can make stack traces harder to read.

Definition of done

For all known asynchronous functions:

• add async keyword
• undo wrapping in Promise.resolve().then(…) if applicable
• undo any explicit result wrapping
  return Promise.resolve(…) ⮕ return …
• throw errors instead of returning rejections
  return Promise.reject(new Error(…)) ⮕ throw new Error(…)
• optional: use await & try/catch in the function body instead of traditional promise handling

Task list

Tools/libs

• cordova-cli
• cordova-lib
• cordova-create
• cordova-fetch (src-only: refactor: use async/await where applicable cordova-fetch#89)
• cordova-common
• cordova-serve
• cordova-js (only the Node.js part)

Platforms (only the Node.js part)

• cordova-android
• cordova-browser
• cordova-ios
• cordova-windows