feat: transpile with babel for proper testing

.gitignore

@@ -1,3 +1,3 @@
 coverage
 node_modules
-test/test-all.js
+dist

README.md

@@ -13,6 +13,13 @@ Add to your project:
 
 `npm i local-storage-poorlyfill`
 
+```html
+<script type="text/javascript" src="node_modules/local-storage-poorlyfill/dist/local-storage-poorlyfill.js"></script>
+<script>
+// use _localStorage
+</script>
+```
+
 ### Why?
 
 - For local files, IE and Edge do not have support for local storage

gulpfile.js

@@ -1,20 +1,73 @@
 const path = require('path')
 const { src, dest, series } = require('gulp')
-const include = require('gulp-include')
-const rename = require('gulp-rename')
+const rollup = require('gulp-rollup')
+const babel = require('gulp-babel')
+const header = require('gulp-header')
 const Server = require('karma').Server
 
+const headerTxt =
+`/**
+ *
+ * Partial local storage polyfill
+ *
+ * @author Patrick Kubiak <[email protected]>
+ *
+ * Why?
+ * - For local files, IE and Edge do not have support for local storage
+ * - local storage can be disabled
+ *
+ * Implementation details:
+ * - Use browser's native implementation if supported
+ * - Mirror native functionality with an object
+ *
+ * Implementation flaws:
+ * - Not persistent
+ * - Need to use _localStorage instead of localStorage
+ *
+ * Use _localStorage or window._localStorage instead of localStorage or window.localStorage
+ * because the browser prevents using localStorage or window.localStorage if access is denied for this document
+ *
+ */
+
+`
+
+/**
+ * Babel transpile for dist
+ */
+function transpile () {
+  return src('./src/**/*.js')
+    .pipe(rollup({
+      input: './src/local-storage-poorlyfill.js',
+      output: {
+        format: 'iife'
+      },
+      plugins: [
+        babel({
+          presets: ['@babel/env']
+        })
+      ]
+    }))
+    .pipe(header(headerTxt))
+    .pipe(dest('./dist/'))
+}
+
 /**
- * Combine polyfill and tests into ./test/test-all.js
+ * Babel transpile for tests
  */
-function combine () {
-  return src('./test/test.js')
-    .pipe(include())
-    .on('error', console.log)
-    .pipe(rename({
-      suffix: '-all'
+function transpileTests () {
+  return src(['./src/**/*.js', './test/**/*.js'])
+    .pipe(rollup({
+      input: './test/test.js',
+      output: {
+        format: 'iife'
+      },
+      plugins: [
+        babel({
+          presets: ['@babel/env']
+        })
+      ]
     }))
-    .pipe(dest('./test/'))
+    .pipe(dest('./dist/'))
 }
 
 /**
@@ -27,9 +80,14 @@ function test (done) {
   }, done()).start()
 }
 
-const runTests = series(combine, test)
+/**
+ * Transpile and run tests
+ */
+const runTests = series(transpileTests, test)
 
-exports.combine = combine
+// export
+exports.transpile = transpile
+exports.transpileTests = transpileTests
 exports.test = test
 exports.runTests = runTests
 exports.default = runTests

karma.conf.js

@@ -13,7 +13,7 @@ module.exports = function (config) {
 
     // list of files / patterns to load in the browser
     files: [
-      'test/test-all.js'
+      'dist/test.js'
     ],
 
     // list of files / patterns to exclude
@@ -23,7 +23,7 @@ module.exports = function (config) {
     // preprocess matching files before serving them to the browser
     // available preprocessors: https://npmjs.org/browse/keyword/karma-preprocessor
     preprocessors: {
-      'test/test-all.js': 'coverage'
+      'dist/test.js': 'coverage'
     },
 
     // test results reporter to use

package.json

@@ -2,8 +2,10 @@
   "name": "local-storage-poorlyfill",
   "version": "0.0.0-development",
   "description": "in-memory polyfill for local storage",
-  "main": "\"\"",
+  "main": "src/local-storage-poorlyfill.js",
   "directories": {
+    "dist": "dist",
+    "src": "src",
     "test": "test"
   },
   "scripts": {
@@ -26,10 +28,18 @@
     "url": "https://github.com/patkub/local-storage-poorlyfill/issues"
   },
   "homepage": "https://github.com/patkub/local-storage-poorlyfill#readme",
-  "dependencies": {},
+  "dependencies": {
+    "@babel/polyfill": "^7.6.0",
+    "gulp-babel": "^8.0.0",
+    "gulp-rollup": "^2.16.2"
+  },
   "devDependencies": {
+    "@babel/cli": "^7.6.3",
+    "@babel/core": "^7.6.3",
+    "@babel/preset-env": "^7.6.3",
     "chai": "^4.2.0",
     "gulp": "^4.0.2",
+    "gulp-header": "^2.0.9",
     "gulp-include": "^2.4.1",
     "gulp-rename": "^1.4.0",
     "karma": "^4.3.0",
@@ -42,6 +52,8 @@
     "mocha": "^6.2.1",
     "semantic-release": "^15.13.24",
     "sinon": "^7.5.0",
-    "standard": "^14.3.1"
+    "standard": "^14.3.1",
+    "vinyl-buffer": "^1.0.1",
+    "vinyl-source-stream": "^2.0.0"
   }
 }

src/local-storage-poorlyfill.js

@@ -0,0 +1,11 @@
+import { _localStorage, _isSupported } from './local-storage.js'
+
+if (_isSupported()) {
+  // use browser's implementation
+  // cannot overwrite window.localStorage
+  window._localStorage = window.localStorage
+} else {
+  // mirror functionality with an object
+  // cannot overwrite window.localStorage
+  window._localStorage = _localStorage
+}

src/local-storage.js

@@ -0,0 +1,80 @@
+// strict mode
+'use strict'
+
+// internal object to hold data
+let _storage = {}
+
+/**
+ * @param key key to item
+ * @param {String} value key's value
+ */
+const setItem = function (key, value) {
+  _storage[key] = String(value)
+}
+
+/**
+ * @return item or null if it does not exist
+ */
+const getItem = function (key) {
+  if (Object.prototype.hasOwnProperty.call(_storage, key)) {
+    return _storage[key]
+  }
+  return null
+}
+
+/**
+ * @return undefined
+ */
+const removeItem = function (key) {
+  if (Object.prototype.hasOwnProperty.call(_storage, key)) {
+    delete _storage[key]
+  }
+  return undefined
+}
+
+/**
+ * @return undefined
+ */
+const clear = function () {
+  _storage = {}
+}
+
+/**
+ * Check if localStorage is supported by the browser
+ * @return {Boolean} true if supported, false otherwise
+ */
+const _isSupported = function () {
+  // assume it's supported
+  var supported = true
+
+  try {
+    // check if the browser allows access to local storage
+    // it should be truthy, and it should be an object
+    // ie window.localStorage is undefined
+    if (!window.localStorage || !(typeof window.localStorage === 'object')) {
+      supported = false
+    }
+  } catch (e) {
+    // chrome and opera throw DOMException
+    // safari throws SecurityError
+    // edge throws Unspecified error
+    supported = false
+  }
+
+  return supported
+}
+
+// local storage methods
+const _localStorage = {
+  setItem: setItem,
+  getItem: getItem,
+  removeItem: removeItem,
+  clear: clear
+}
+
+// export
+export {
+  _localStorage,
+  _isSupported,
+  _storage
+}