Alternate Appflow Build Command
For generating the web build Appflow will use the build script defined in the package.json, unless there is a script named appflow:build defined.
In the scripts section of the package.json for an Application define a appflow:build element. It can be any command valid as a npm script.
For example: package.json
{
  "name": "AppFlowTest",
  "version": "0.0.1",
  "private": true,
  "scripts": {
    "appflow:build": "some-build-command",
  },
...