First commit

Author: kouts

.eslintrc

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+{
+    "extends": [ "eslint:recommended" ],
+    "env": {
+        "node": false,
+        "browser": true
+    },
+    "parserOptions": {
+        "ecmaVersion": 2017,
+        "sourceType": "module"
+    },
+    "rules": {
+        "no-console": "off",
+        "no-unused-vars": "warn",
+        "quotes": [
+        	"error",
+        	"single"
+        ],
+        "semi": [
+            2,
+            "always"
+        ]
+    },
+    "globals": {
+        "Promise": true,
+        "System": true
+    },
+    "overrides": [{
+        "files": "",
+        "rules": {
+        	"quotes": [2, "double"]
+        }
+    }]
+}

.gitignore

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+node_modules

README.md

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+systemjs-css-extra
+===
+
+Simple CSS loader extra for SystemJS v4 and up

build/build.js

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+const fs = require('fs');
+const babel = require('@babel/core');
+
+// Transpile to ES5
+let transpiled = babel.transformFileSync('src/css.js', {
+  configFile: false,
+  comments: false,
+  sourceMaps: false,
+  presets: ['@babel/preset-env']
+});
+
+// Transpile to ES5 and minify
+let transpiled_minified = babel.transformFileSync('src/css.js', {
+  configFile: false,
+  comments: false,
+  sourceMaps: false,
+  presets: ['@babel/preset-env', 'minify']
+});
+
+fs.writeFileSync('dist/css.js', transpiled.code);
+fs.writeFileSync('dist/css.min.js', transpiled_minified.code);

dist/css.js

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+'use strict';
+
+(function () {
+  var systemPrototype = System.constructor.prototype;
+  var originalInstantiate = systemPrototype.instantiate;
+
+  systemPrototype.instantiate = function () {
+    var loader = this;
+    var url = arguments[0];
+
+    if (url.slice(-4) === '.css') {
+      return new Promise(function (resolve, reject) {
+        if (document.querySelector('link[href="' + url + '"]') || document.querySelector('link[href="' + url.replace(location.protocol + '//' + location.hostname, '') + '"]')) {
+          reject(Error('Style ' + url + ' has already been loaded'));
+        }
+
+        var link = document.createElement('link');
+        link.type = 'text/css';
+        link.rel = 'stylesheet';
+        link.href = url;
+        document.head.appendChild(link);
+
+        link.onload = function () {
+          resolve(loader.getRegister());
+        };
+
+        link.onerror = function () {
+          var href = document.querySelector('link[href="' + url + '"]');
+
+          if (href) {
+            href.parentElement.removeChild(href);
+          }
+
+          reject(Error('Style ' + url + ' has failed loading'));
+        };
+      });
+    } else {
+      return originalInstantiate.apply(this, arguments);
+    }
+  };
+})();