Update setup for consistent codewell packaging

Updates the project to use similar setup as
the one generated by the new-package script.

.gitignore

@@ -1,2 +1,3 @@
 node_modules
-.npmrc
+.npmrc
+lib

.npmignore

@@ -0,0 +1,4 @@
+src
+tests
+.prettierrc
+rollup.config.js

index.js

@@ -0,0 +1,5 @@
+if (process.env.NODE_ENV === "production") {
+  module.exports = require("./lib/prod");
+} else {
+  module.exports = require("./lib/dev");
+}

package.json

@@ -4,7 +4,12 @@
   "description": "State persistor for front end applications",
   "main": "src/index.js",
   "scripts": {
-    "test": "echo \"Error: no test specified\" && exit 1"
+    "test": "jest",
+    "build": "rollup --config",
+    "release": "npm run build:dev && npm run build:prod",
+    "build:prod": "NODE_ENV=production rollup -c",
+    "build:dev": "NODE_ENV=development rollup -c",
+    "dry-release": "npm run release && npm pack"
   },
   "repository": {
     "type": "git",
@@ -20,5 +25,27 @@
   "bugs": {
     "url": "https://github.com/codewell/state-persistor/issues"
   },
-  "homepage": "https://github.com/codewell/state-persistor#readme"
-}
+  "homepage": "https://github.com/codewell/state-persistor#readme",
+  "devDependencies": {
+    "@babel/core": "^7.8.4",
+    "@babel/preset-env": "^7.8.4",
+    "@rollup/plugin-replace": "^2.3.1",
+    "husky": "^4.2.3",
+    "jest": "^25.1.0",
+    "lint-staged": "^10.0.7",
+    "prettier": "^1.19.1",
+    "rollup": "^1.31.1",
+    "rollup-plugin-babel": "^4.3.3",
+    "rollup-plugin-commonjs": "^10.1.0",
+    "rollup-plugin-node-resolve": "^5.2.0",
+    "rollup-plugin-peer-deps-external": "^2.2.2"
+  },
+  "husky": {
+    "hooks": {
+      "pre-commit": "lint-staged"
+    }
+  },
+  "lint-staged": {
+    "*.{js,css,md}": "prettier --write"
+  }
+}

rollup.config.js

@@ -0,0 +1,32 @@
+import babel from "rollup-plugin-babel";
+import resolve from "rollup-plugin-node-resolve";
+import commonjs from "rollup-plugin-commonjs";
+import replace from "@rollup/plugin-replace";
+import peerDepsExternal from "rollup-plugin-peer-deps-external";
+
+const NODE_ENV = process.env.NODE_ENV || "development";
+const outputFile = NODE_ENV === "production" ? "./lib/prod.js" : "./lib/dev.js";
+const extensions = [".js"];
+
+export default {
+  input: "./src/index.js",
+  output: {
+    file: outputFile,
+    format: "cjs"
+  },
+  plugins: [
+    peerDepsExternal(),
+    replace({
+      "process.env.NODE_ENV": JSON.stringify(NODE_ENV)
+    }),
+    babel({
+      exclude: "node_modules/**",
+      presets: [["@babel/preset-env", { modules: false }]],
+      extensions
+    }),
+    resolve({
+      extensions
+    }),
+    commonjs()
+  ]
+};

src/index.js

@@ -1,9 +1,5 @@
-const loadState = require('./loadState');
-const purgeState = require('./purgeState');
-const saveState = require('./saveState');
+import loadState from "./loadState";
+import purgeState from "./purgeState";
+import saveState from "./saveState";
 
-module.exports = {
-  loadState,
-  purgeState,
-  saveState,
-};
+export { loadState, purgeState, saveState };

src/loadState.js

@@ -3,7 +3,7 @@
  * @param {string} storageKey - What key in localstorage to load from
  * @returns {Object} - Returns the persisted state
  */
-const loadState = (storageKey) => {
+const loadState = storageKey => {
   try {
     const serializedState = localStorage.getItem(storageKey);
     if (serializedState === null) {
@@ -15,4 +15,4 @@ const loadState = (storageKey) => {
   }
 };
 
-module.exports = loadState;
+export default loadState;

src/purgeState.js

@@ -2,12 +2,12 @@
  * Remove everything from local storage
  * @param {string} storageKey - What key in localstorage to purge
  */
-const purgeState = (storageKey) => {
+const purgeState = storageKey => {
   try {
     localStorage.removeItem(storageKey);
   } catch (error) {
     // Ignore write errors
   }
 };
 
-module.exports = purgeState;
+export default purgeState;

src/saveState.js

@@ -12,4 +12,4 @@ const saveState = (state, storageKey) => {
   }
 };
 
-module.exports = saveState;
+export default saveState;