Roughing out the demo app

node_modules/lowdb/adapters/FileAsync.js

@@ -0,0 +1,65 @@
+'use strict';
+
+var _createClass = function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; }();
+
+function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }
+
+function _possibleConstructorReturn(self, call) { if (!self) { throw new ReferenceError("this hasn't been initialised - super() hasn't been called"); } return call && (typeof call === "object" || typeof call === "function") ? call : self; }
+
+function _inherits(subClass, superClass) { if (typeof superClass !== "function" && superClass !== null) { throw new TypeError("Super expression must either be null or a function, not " + typeof superClass); } subClass.prototype = Object.create(superClass && superClass.prototype, { constructor: { value: subClass, enumerable: false, writable: true, configurable: true } }); if (superClass) Object.setPrototypeOf ? Object.setPrototypeOf(subClass, superClass) : subClass.__proto__ = superClass; }
+
+// Not using async/await on purpose to avoid adding regenerator-runtime
+// to lowdb dependencies
+var fs = require('graceful-fs');
+var pify = require('pify');
+var steno = require('steno');
+var Base = require('./Base');
+
+var readFile = pify(fs.readFile);
+var writeFile = pify(steno.writeFile);
+
+var FileAsync = function (_Base) {
+  _inherits(FileAsync, _Base);
+
+  function FileAsync() {
+    _classCallCheck(this, FileAsync);
+
+    return _possibleConstructorReturn(this, (FileAsync.__proto__ || Object.getPrototypeOf(FileAsync)).apply(this, arguments));
+  }
+
+  _createClass(FileAsync, [{
+    key: 'read',
+    value: function read() {
+      var _this2 = this;
+
+      // fs.exists is deprecated but not fs.existsSync
+      if (fs.existsSync(this.source)) {
+        // Read database
+        return readFile(this.source, 'utf-8').then(function (data) {
+          // Handle blank file
+          var trimmed = data.trim();
+          return trimmed ? _this2.deserialize(trimmed) : _this2.defaultValue;
+        }).catch(function (e) {
+          if (e instanceof SyntaxError) {
+            e.message = `Malformed JSON in file: ${_this2.source}\n${e.message}`;
+          }
+          throw e;
+        });
+      } else {
+        // Initialize
+        return writeFile(this.source, this.serialize(this.defaultValue)).then(function () {
+          return _this2.defaultValue;
+        });
+      }
+    }
+  }, {
+    key: 'write',
+    value: function write(data) {
+      return writeFile(this.source, this.serialize(data));
+    }
+  }]);
+
+  return FileAsync;
+}(Base);
+
+module.exports = FileAsync;