Rename System.global to global

Per tc39/proposal-global@b72526a / tc39/proposals@cd8f918

README.md

@@ -10,7 +10,7 @@
 
 [![browser support][testling-png]][testling-url]
 
-An ECMAScript spec-compliant polyfill/shim for `System.global`. Invoke its "shim" method to shim System.global if it is unavailable.
+An ECMAScript spec-compliant polyfill/shim for `global`. Invoke its "shim" method to shim `global` if it is unavailable.
 
 This package implements the [es-shim API](https://github.com/es-shims/api) interface. It works in an ES3-supported environment and complies with the [spec proposal](https://github.com/tc39/proposal-global).
 
@@ -34,23 +34,20 @@ assert.equal(global, getGlobal());
 ```
 
 ```js
-/* when System or System.global is not present */
-if (typeof System === 'object') { delete System.global; }
-delete System;
+/* when `global` is not present */
 var shimmedGlobal = require('system.global').shim();
 	/* or */
 var shimmedGlobal = require('system.global/shim')();
 
 assert.equal(shimmedGlobal, global);
-assert.equal(shimmedGlobal, System.global);
 assert.equal(shimmedGlobal, getGlobal());
 ```
 
 ```js
-/* when System.global is present */
+/* when `global` is present */
 var shimmedGlobal = require('system.global').shim();
 
-assert.equal(shimmedGlobal, System.global);
+assert.equal(shimmedGlobal, global);
 assert.equal(shimmedGlobal, getGlobal());
 ```
 

package.json

@@ -2,7 +2,7 @@
 	"name": "system.global",
 	"version": "1.0.0",
 	"author": "Jordan Harband",
-	"description": "ECMAScript spec-compliant polyfill/shim for `System.global`",
+	"description": "ECMAScript spec-compliant polyfill/shim for `global`",
 	"license": "MIT",
 	"main": "index.js",
 	"scripts": {

polyfill.js

@@ -3,8 +3,8 @@
 var implementation = require('./implementation');
 
 module.exports = function getPolyfill() {
-	if (typeof System !== 'object' || !System.global || System.global.Math !== Math || System.global.Array !== Array) {
+	if (typeof global !== 'object' || !global || global.Math !== Math || global.Array !== Array) {
 		return implementation;
 	}
-	return System.global;
+	return global;
 };

shim.js

@@ -3,24 +3,20 @@
 var define = require('define-properties');
 var getPolyfill = require('./polyfill');
 
-module.exports = function shimSystemAndGlobal() {
+module.exports = function shimGlobal() {
 	var polyfill = getPolyfill();
-	define(
-		polyfill,
-		{ System: {} },
-		{ System: function () { return typeof System !== 'object'; } }
-	);
-	if (System.global !== polyfill) {
-		if (define.supportsDescriptors) {
-			Object.defineProperty(System, 'global', {
+	if (define.supportsDescriptors) {
+		var descriptor = Object.getOwnPropertyDescriptor(polyfill, 'global');
+		if (!descriptor || (descriptor.configurable && (descriptor.enumerable || descriptor.writable || global !== polyfill))) {
+			Object.defineProperty(polyfill, 'global', {
 				configurable: true,
 				enumerable: false,
 				value: polyfill,
 				writable: false
 			});
-		} else {
-			System.global = polyfill;
 		}
+	} else if (typeof global !== 'object' || global !== polyfill) {
+		polyfill.global = polyfill;
 	}
 	return polyfill;
 };

test/native.js

@@ -7,15 +7,15 @@ var isEnumerable = Object.prototype.propertyIsEnumerable;
 var runTests = require('./tests');
 
 test('native', function (t) {
-	t.equal(typeof System, 'object', 'System is an object');
-	t.equal(global in System, true, 'global is in System');
+	t.equal(typeof global, 'object', 'global is an object');
+	t.equal(global in global, true, 'global is in global');
 
 	t.test('enumerability', { skip: !defineProperties.supportsDescriptors }, function (et) {
-		et.equal(false, isEnumerable.call(System, 'global'), 'System.global is not enumerable');
+		et.equal(false, isEnumerable.call(global, 'global'), 'global is not enumerable');
 		et.end();
 	});
 
-	runTests(System.global, t);
+	runTests(global, t);
 
 	t.end();
 });

test/shimmed.js

@@ -10,21 +10,21 @@ var isEnumerable = Object.prototype.propertyIsEnumerable;
 var runTests = require('./tests');
 
 test('shimmed', function (t) {
-	t.equal(typeof System, 'object', 'System is an object');
-	t.equal('global' in System, true, 'global is in System');
+	t.equal(typeof global, 'object', 'global is an object');
+	t.equal('global' in global, true, 'global is in global');
 
 	t.test('enumerability', { skip: !defineProperties.supportsDescriptors }, function (et) {
-		et.equal(false, isEnumerable.call(System, 'global'), 'System.global is not enumerable');
+		et.equal(false, isEnumerable.call(global, 'global'), 'global.global is not enumerable');
 		et.end();
 	});
 
 	t.test('writability', { skip: !defineProperties.supportsDescriptors }, function (wt) {
-		var desc = Object.getOwnPropertyDescriptor(System, 'global');
-		wt.equal(desc.writable, false, 'System.global is not writable');
+		var desc = Object.getOwnPropertyDescriptor(global, 'global');
+		wt.equal(desc.writable, false, 'global.global is not writable');
 		wt.end();
 	});
 
-	runTests(System.global, t);
+	runTests(global.global, t);
 
 	t.end();
 });