build a separate file that defines globals in the browser

This way axs can be built from npm _and_ be available to execute in the
browser

lib/accessibility.js

@@ -2,7 +2,7 @@ const Eval = require('./eval')
 
 exports.audit = () => {
   return Eval.execute(function () {
-    const {axs} = window
+    const {axs} = window.__devtron // defined in browserGlobals.js
     const config = new axs.AuditConfiguration({showUnsupportedRulesWarning: false})
     const results = axs.Audit.run(config)
 

lib/browserGlobals.js

@@ -0,0 +1,8 @@
+// This defines globals that will be used in the browser context
+// (via the content_scripts definition in manifest.json)
+//
+// It is generated via `npm run-script prepublish`
+const axs = require('accessibility-developer-tools')
+
+window.__devtron = window.__devtron || {}
+window.__devtron.axs = axs

manifest.json

@@ -5,7 +5,7 @@
   "content_scripts": [
     {
       "matches": ["*"],
-      "js": ["node_modules/accessibility-developer-tools/dist/js/axs_testing.js"]
+      "js": ["out/browserGlobals.js"]
     }
   ]
 }

package.json

@@ -4,7 +4,7 @@
   "description": "Electron DevTools Extension",
   "main": "./api.js",
   "scripts": {
-    "prepublish": "browserify lib/*.js -o out/index.js --ignore-missing --entry lib/index.js",
+    "prepublish": "browserify lib/*.js -o out/index.js --ignore-missing --entry lib/index.js && browserify lib/browserGlobals.js -o out/browserGlobals.js",
     "start": "watchify lib/*.js -o out/index.js --ignore-missing --entry lib/index.js --verbose",
     "test": "mocha test/unit/*-test.js test/integration/*-test.js && standard"
   },