Merge pull request #17 from pzuraq/adds-error-for-ie-11

[FEAT] Adds error when attempting to use in IE11

README.md

@@ -1,6 +1,10 @@
 tracked-built-ins
 ==============================================================================
 
+> **IMPORTANT: This addon does _NOT_ support IE 11 or older browsers. If you
+> need to support them, consider using [tracked-maps and sets](https://github.com/pzuraq/tracked-maps-and-sets)
+> instead.**
+
 This addon provides tracked versions of JavaScript's built-ins:
 
 ```js

index.js

@@ -1,5 +1,13 @@
 'use strict';
 
 module.exports = {
-  name: require('./package').name
+  name: require('./package').name,
+
+  included() {
+    this._super.included.apply(this, arguments);
+
+    if (this.project.targets.browsers.includes('ie 11')) {
+      throw new Error('`tracked-built-ins` uses Proxy, which is not supported in IE 11 or other older browsers. You have included IE 11 in your targets, which is not supported. Consider using `tracked-maps-and-sets`, which does support IE 11.');
+    }
+  }
 };

tests/dummy/config/targets.js

@@ -1,18 +1,12 @@
 'use strict';
 
 const browsers = [
-  'last 1 Chrome versions',
-  'last 1 Firefox versions',
-  'last 1 Safari versions',
+  'last 2 Chrome versions',
+  'last 2 Firefox versions',
+  'last 2 Safari versions',
+  'last 2 Edge versions',
 ];
 
-const isCI = !!process.env.CI;
-const isProduction = process.env.EMBER_ENV === 'production';
-
-if (isCI || isProduction) {
-  browsers.push('ie 11');
-}
-
 module.exports = {
   browsers,
 };