lightweight json wrapper for w3c Storage engines

README.md

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+jsonStorage
+====
+
+A light abstraction for DOMStorage (such as localStorage).
+
+Made fo for Node.JS and Ender.JS (browser-side).
+
+    var localStorage = require('localStorage')
+      , JsonStorage = require('json-storage')
+      , db = JsonStorage(localStorage)
+      , myValue = {
+            foo: "bar"
+          , baz: "quux"
+        }
+      ;
+
+    db.set('myKey', myValue); 
+    myValue = db.get('myKey');
+
+API
+===
+
+  * get(key)
+  * set(key, value)
+  * remove(key)
+  * clear()
+  * keys()
+  * size()
+
+null vs undefined in JSON
+===
+
+Since it is not valid to set `undefined` in JSON, calling `db.set('x')` is the same as `db.remove('x')`.
+
+However, `null`, and `"null"` both parse as `null` the "object", but the string (which would be `"\"null\""`).
+
+Therefore, setting a key to `undefined` will remove it from the db, but setting it to `null` will save it.
+
+Yet both values that exist as `null` and values that don't exist will return `null`.
+
+Also `{ "foo": null, "bar": "null" }` will parse as `foo` being `null` but `bar` being `"null"`, much unlike the value `"null"` being parsed on its own.

lib/json-storage.js

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+(function () {
+  "use strict";
+
+  var db;
+
+  function Stringify(obj) {
+    var str;
+    try {
+      str = JSON.stringify(obj);
+    } catch(e) {
+      str = "";
+    }
+
+    return str;
+  }
+
+  function Parse(str) {
+    var obj = null;
+    try {
+      obj = JSON.parse(str);
+    } catch(e) {}
+
+    return obj;
+  }
+
+  function JsonStorage(w3cStorage) {
+    this.db = w3cStorage;
+    this.keysAreDirty = true;
+  }
+  db = JsonStorage;
+  
+  db.prototype.clear = function () {
+    this.keysAreDirty = true;
+    self.keys().forEach(function (uuid) {
+      this.remove(uuid);
+    }, this);
+  };
+
+  db.prototype.remove = function (uuid) {
+    this.keysAreDirty = true;
+    this.db.removeItem(uuid);
+  };
+
+  db.prototype.get = function (uuid) {
+    return Parse(this.db.getItem(uuid));
+  };
+
+  db.prototype.set = function (uuid, val) {
+    this.keysAreDirty = true;
+    return this.db.setItem(uuid, Stringify(val));
+  };
+
+  db.prototype.keys = function () {
+    var i;
+
+    if (!this.keysAreDirty) {
+      return this.keys;
+    }
+
+    this.keys = [];
+    for (i = 0; i < this.db.length; i += 1) {
+      this.keys.push(this.db.key(i));
+    }
+    this.keysAreDirty = false;
+    return this.keys.concat([]);
+  };
+
+  db.prototype.size = function () {
+    return this.db.length;
+  };
+
+  function create(w3cStorage) {
+    return new JsonStorage(w3cStorage);
+  }
+
+  module.exports = create;
+}());

lib/package.json

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+{
+  "author": "AJ ONeal <coolaj86@gmail.com> (http://coolaj86.info)",
+  "name": "json-storage",
+  "description": "A wrapper for storage engines which use the W3C Storage API",
+  "keywords": ["ender", "localStorage", "sessionStorage", "globalStorage", "Storage"],
+  "version": "1.0.0",
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/coolaj86/json-storage-js.git"
+  },
+  "engines": {
+    "node": ">= v0.2.0"
+  },
+  "main": "json-storage.js",
+  "dependencies": {},
+  "devDependencies": {}
+}

tests/node_modules/json-storage/json-storage.js

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+(function () {
+  "use strict";
+
+  var db;
+
+  function Stringify(obj) {
+    var str;
+    try {
+      str = JSON.stringify(obj);
+    } catch(e) {
+      str = "";
+    }
+
+    return str;
+  }
+
+  function Parse(str) {
+    var obj = null;
+    try {
+      obj = JSON.parse(str);
+    } catch(e) {}
+
+    return obj;
+  }
+
+  function JsonStorage(w3cStorage) {
+    this.db = w3cStorage;
+    this.keysAreDirty = true;
+  }
+  db = JsonStorage;
+  
+  db.prototype.clear = function () {
+    this.keysAreDirty = true;
+    self.keys().forEach(function (uuid) {
+      this.remove(uuid);
+    }, this);
+  };
+
+  db.prototype.remove = function (uuid) {
+    this.keysAreDirty = true;
+    this.db.removeItem(uuid);
+  };
+
+  db.prototype.get = function (uuid) {
+    return Parse(this.db.getItem(uuid));
+  };
+
+  db.prototype.set = function (uuid, val) {
+    this.keysAreDirty = true;
+    return this.db.setItem(uuid, Stringify(val));
+  };
+
+  db.prototype.keys = function () {
+    var i;
+
+    if (!this.keysAreDirty) {
+      return this.keys;
+    }
+
+    this.keys = [];
+    for (i = 0; i < this.db.length; i += 1) {
+      this.keys.push(this.db.key(i));
+    }
+    this.keysAreDirty = false;
+    return this.keys.concat([]);
+  };
+
+  db.prototype.size = function () {
+    return this.db.length;
+  };
+
+  function create(w3cStorage) {
+    return new JsonStorage(w3cStorage);
+  }
+
+  module.exports = create;
+}());

tests/node_modules/json-storage/package.json

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+{
+  "author": "AJ ONeal <coolaj86@gmail.com> (http://coolaj86.info)",
+  "name": "json-storage",
+  "description": "A wrapper for storage engines which use the W3C Storage API",
+  "keywords": ["ender", "localStorage", "sessionStorage", "globalStorage", "Storage"],
+  "version": "1.0.0",
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/coolaj86/json-storage-js.git"
+  },
+  "engines": {
+    "node": ">= v0.2.0"
+  },
+  "main": "json-storage.js",
+  "dependencies": {},
+  "devDependencies": {}
+}

tests/node_modules/localStorage/localStorage.js

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+// http://www.rajdeepd.com/articles/chrome/localstrg/LocalStorageSample.htm
+
+// NOTE:
+// this varies from actual localStorage in some subtle ways
+
+// also, there is no persistence
+// TODO persist
+(function () {
+  "use strict";
+
+  var db;
+
+  function LocalStorage() {
+  }
+  db = LocalStorage;
+
+  db.prototype.getItem = function (key) {
+    if (key in this) {
+      return String(this[key]);
+    }
+    return null;
+  };
+
+  db.prototype.setItem = function (key, val) {
+    this[key] = String(val);
+  };
+
+  db.prototype.removeItem = function (key) {
+    delete this[key];
+  };
+
+  db.prototype.clear = function () {
+    var self = this;
+    Object.keys(self).forEach(function (key) {
+      self[key] = undefined;
+      delete self[key];
+    });
+  };
+
+  db.prototype.key = function (i) {
+    i = i || 0;
+    return Object.keys(this)[i];
+  };
+
+  db.prototype.__defineGetter__('length', function () {
+    return Object.keys(this).length;
+  });
+
+  if (global.localStorage) {
+    module.exports = localStorage;
+  } else {
+    module.exports = new LocalStorage();
+  }
+}());

tests/node_modules/localStorage/package.json

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+{
+  "author": "AJ ONeal <coolaj86@gmail.com> (http://coolaj86.info)",
+  "name": "localStorage",
+  "description": "W3C localStorage for Node.JS",
+  "version": "1.0.0",
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/coolaj86/node-localStorage.git"
+  },
+  "engines": {
+    "node": ">= v0.2.0"
+  },
+  "main": "localStorage.js",
+  "dependencies": {},
+  "devDependencies": {}
+}

tests/test.js

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+(function () {
+  "use strict";
+
+  var assert = require('assert')
+    , localStorage = require('localStorage')
+    , JsonStorage = require('json-storage')
+    , db = JsonStorage(localStorage)
+    ;
+
+  assert.strictEqual(null, db.get('a'));
+
+  // you can't really save undefined as JSON, it's not valid
+  // the attempt to do so will delete the underlying key
+  db.set('a');
+  assert.strictEqual(null, db.get('a'));
+
+  db.set('a', 1);
+  assert.strictEqual(1, db.get('a'));
+
+  db.set('a', '1');
+  assert.strictEqual('1', db.get('a'));
+
+  db.set('a', [1]);
+  assert.deepEqual([1], db.get('a'));
+
+  db.set('a', { 'a': [1] });
+  assert.deepEqual({'a': [1] }, db.get('a'));
+}());