Add detector for Expo

src/detectors/expo.js

@@ -0,0 +1,32 @@
+const { hasRequiredDeps, hasRequiredFiles, getYarnOrNPMCommand, scanScripts } = require('./utils/jsdetect')
+module.exports = function() {
+  // REQUIRED FILES
+  if (!hasRequiredFiles(['package.json', 'app.json'])) return false
+  // REQUIRED DEPS
+  if (!hasRequiredDeps(['expo'])) return false
+
+  /** everything below now assumes that we are within expo */
+
+  const possibleArgsArrs = scanScripts({
+    // prefer the `start:web` script instead of expo's default `web` since that runs
+    // `expo start --web`, which auto launches the (non-proxied) web browser.
+    preferredScriptsArr: ['start:web'],
+    // `expo start:web` does not auto launch the web browser
+    preferredCommand: 'expo start:web'
+  })
+
+  if (possibleArgsArrs.length === 0) {
+    // ofer to run it when the user doesnt have any scripts setup! 🤯
+    possibleArgsArrs.push(['expo', 'start:web'])
+  }
+  return {
+    type: 'expo',
+    command: getYarnOrNPMCommand(),
+    port: 8888,
+    proxyPort: 19006,
+    env: { ...process.env },
+    possibleArgsArrs,
+    urlRegexp: new RegExp(`(http://)([^:]+:)${19006}(/)?`, 'g'),
+    dist: 'web-build'
+  }
+}