fix(darwin): wrong display capturing on multi-monitor.

Author: tai2

lib/darwin/index.js

@@ -119,6 +119,20 @@ function makeSubtree (currIndent, subtree, entries) {
   }
 }
 
+function movePrimaryToHead (displays) {
+  const primary = displays.filter(e => e.primary)
+  const notPrimary = displays.filter(e => !e.primary)
+  return [...primary, ...notPrimary]
+}
+
+function addId (displays) {
+  let id = 0
+  return displays
+    .map(display => {
+      return Object.assign({}, display, { id: id++ })
+    })
+}
+
 function parseDisplaysOutput (output) {
   const tree = {}
   makeSubtree(-1, tree, extractEntries(output))
@@ -137,12 +151,13 @@ function parseDisplaysOutput (output) {
     return []
   }
 
-  let id = 0
-  return Object.entries(firstGpu['Displays'])
+  const displays = Object.entries(firstGpu['Displays'])
     .map(([name, props]) => {
-      id++
-      return { id, name }
+      const primary = props['Main Display'] === 'Yes'
+      return { name, primary }
     })
+
+  return addId(movePrimaryToHead(displays))
 }
 
 function listDisplays () {