New has function & safer testing.

Tests updated with DB cleanup after every task.

.gitignore

@@ -3,24 +3,12 @@
 
 ### Node ###
 # Logs
-# Runtime data
-# Directory for instrumented libs generated by jscoverage/JSCover
-# Coverage directory used by tools like istanbul
-# nyc test coverage
-# Grunt intermediate storage (http://gruntjs.com/creating-plugins#storing-task-files)
-# node-waf configuration
-# Compiled binary addons (http://nodejs.org/api/addons.html)
+npm-debug.log
 # Dependency directories
 node_modules
-# Optional npm cache directory
-# Optional REPL history
 ### WebStorm ###
 # Covers JetBrains IDEs: IntelliJ, RubyMine, PhpStorm, AppCode, PyCharm, CLion, Android Studio and Webstorm
 # Reference: https://intellij-support.jetbrains.com/hc/en-us/articles/206544839
 
 # Project folder:
-.idea
-
-# IntelliJ
-# mpeltonen/sbt-idea plugin
-# JIRA plugin
+.idea

README.md

@@ -33,6 +33,11 @@ The `key` parameter must be a string, `value` can be whatever kind of object can
 
 The `key` parameter must be a string. If the key exhists its value is returned, if it doesn't the function returns `undefined`.
 
+### Check a key
+`db.has('key');`
+
+The `key` parameter must be a string. If the key exhists `true` is returned, if it doesn't the function returns `false`.
+
 ### Delete a key
 
 `db.delete('key');`

dist/jsondb.js

@@ -26,7 +26,7 @@ var validateJSON = function validateJSON(fileContent) {
 };
 
 /**
- * Main constructor, manages exhisting storage file and parses options against default ones.
+ * Main constructor, manages existing storage file and parses options against default ones.
  * @param {string} filePath The path of the file to use as storage.
  * @param {object} [options] Configuration options.
  * @param {boolean} [options.asyncWrite] Enables the storage to be asynchronously written to disk. Disabled by default (synchronous behaviour).
@@ -54,20 +54,20 @@ function JSONdb(filePath, options) {
   // Storage initialization
   this.storage = {};
 
-  // File exhistence check
+  // File existence check
   var stats = void 0;
   try {
     stats = fs.statSync(filePath);
   } catch (err) {
     if (err.code === 'ENOENT') {
-      /* File doesn't exhist */
+      /* File doesn't exist */
       return;
     } else {
       // Other error
       throw err; // TODO: Check perm
     }
   }
-  /* File exhists */
+  /* File exists */
   try {
     fs.accessSync(filePath, fs.constants.R_OK | fs.constants.W_OK);
   } catch (err) {
@@ -97,12 +97,21 @@ JSONdb.prototype.set = function (key, value) {
 /**
  * Extracts the value of a key from the database.
  * @param {string} key The key to search for.
- * @returns {object|undefined} The value of the key or `undefined` if it doesn't exhist.
+ * @returns {object|undefined} The value of the key or `undefined` if it doesn't exist.
  */
 JSONdb.prototype.get = function (key) {
   return this.storage.hasOwnProperty(key) ? this.storage[key] : undefined;
 };
 
+/**
+ * Checks if a key is contained in the database.
+ * @param {string} key The key to search for.
+ * @returns {boolean} `True` if it exists, `false` if not.
+ */
+JSONdb.prototype.has = function (key) {
+  return this.storage.hasOwnProperty(key);
+};
+
 /**
  * Deletes a key from the database.
  * @param {string} key The key to delete.
@@ -114,6 +123,18 @@ JSONdb.prototype.delete = function (key) {
   return retVal;
 };
 
+/**
+ * Deletes all keys from the database.
+ * @returns {object} The JSONdb instance itself.
+ */
+JSONdb.prototype.deleteAll = function () {
+  for (var key in this.storage) {
+    //noinspection JSUnfilteredForInLoop
+    this.delete(key);
+  }
+  return this;
+};
+
 /**
  * Writes the local storage object to disk.
  */

jsondb.js

@@ -24,7 +24,7 @@ let validateJSON = function(fileContent) {
 };
 
 /**
- * Main constructor, manages exhisting storage file and parses options against default ones.
+ * Main constructor, manages existing storage file and parses options against default ones.
  * @param {string} filePath The path of the file to use as storage.
  * @param {object} [options] Configuration options.
  * @param {boolean} [options.asyncWrite] Enables the storage to be asynchronously written to disk. Disabled by default (synchronous behaviour).
@@ -53,20 +53,20 @@ function JSONdb(filePath, options) {
   // Storage initialization
   this.storage = {};
 
-  // File exhistence check
+  // File existence check
   let stats;
   try {
     stats = fs.statSync(filePath);
   } catch (err) {
     if (err.code === 'ENOENT') {
-      /* File doesn't exhist */
+      /* File doesn't exist */
       return;
     } else {
       // Other error
       throw err;  // TODO: Check perm
     }
   }
-  /* File exhists */
+  /* File exists */
   try {
     fs.accessSync(filePath, fs.constants.R_OK | fs.constants.W_OK);
   } catch (err) {
@@ -96,12 +96,21 @@ JSONdb.prototype.set = function(key, value) {
 /**
  * Extracts the value of a key from the database.
  * @param {string} key The key to search for.
- * @returns {object|undefined} The value of the key or `undefined` if it doesn't exhist.
+ * @returns {object|undefined} The value of the key or `undefined` if it doesn't exist.
  */
 JSONdb.prototype.get = function(key) {
   return this.storage.hasOwnProperty(key) ? this.storage[key] : undefined;
 };
 
+/**
+ * Checks if a key is contained in the database.
+ * @param {string} key The key to search for.
+ * @returns {boolean} `True` if it exists, `false` if not.
+ */
+JSONdb.prototype.has = function(key) {
+  return this.storage.hasOwnProperty(key);
+};
+
 /**
  * Deletes a key from the database.
  * @param {string} key The key to delete.
@@ -113,6 +122,18 @@ JSONdb.prototype.delete = function(key) {
   return retVal;
 };
 
+/**
+ * Deletes all keys from the database.
+ * @returns {object} The JSONdb instance itself.
+ */
+JSONdb.prototype.deleteAll = function() {
+  for (var key in this.storage) {
+    //noinspection JSUnfilteredForInLoop
+    this.delete(key);
+  }
+  return this;
+};
+
 /**
  * Writes the local storage object to disk.
  */

package.json

@@ -1,6 +1,6 @@
 {
   "name": "simple-json-db",
-  "version": "1.1.0",
+  "version": "1.2.0",
   "description": "A simple, no-frills, JSON storage engine for Node.JS",
   "main": "index.js",
   "scripts": {

test.js

@@ -1,7 +1,6 @@
 var JSONdb = require('./jsondb');
 var assert = require('chai').assert;
 var fs = require('fs');
-var filePath = genFilePath();
 
 /**
  * Generates a file path and name based on current UNIX timestamp.
@@ -14,7 +13,7 @@ function genFileName() {
 /**
  * Makes sure that a unique filename is generated.
  */
-function genFilePath() {
+(function genFilePath() {
   while (true) {
     try {
       global.filePath = genFileName();
@@ -23,7 +22,7 @@ function genFilePath() {
       break;
     }
   }
-}
+})();
 
 /**
  * Returns a new instance of JSONdb.
@@ -34,6 +33,10 @@ function createInstance() {
 }
 
 describe("Consistency", function() {
+  beforeEach('Database cleanup', function() {
+    createInstance().deleteAll();
+  });
+
   it("Create a new JSONdb instance and test `instanceOf`", function() {
     var db = createInstance();
     assert.instanceOf(db, JSONdb);
@@ -46,6 +49,10 @@ describe("Consistency", function() {
 });
 
 describe("Mechanics", function() {
+  beforeEach('Database cleanup', function() {
+    createInstance().deleteAll();
+  });
+
   it("Check that values can change", function() {
     var db = createInstance();
     var change = { testVal: db.get('foo') };
@@ -75,6 +82,17 @@ describe("Mechanics", function() {
     assert.isUndefined(secondVal, 'Key was not deleted');
   });
 
+  it("Check that keys existence can be verified (existent key)", function() {
+    var db = createInstance();
+    db.set('foo', Date.now());
+    assert.isTrue(db.has('foo'), 'Key existence is erroneous');
+  });
+
+  it("Check that keys existence can be verified (non-existent key)", function() {
+    var db = createInstance();
+    assert.isFalse(db.has('foo'), 'Key existence is erroneous');
+  });
+
   it("Verify sync to disk", function() {
     var db = createInstance();
     db.set('foo', Date.now());