Completed async nodejs assignment

.gitignore

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+# Created by .ignore support plugin (hsz.mobi)
+### Example user template template
+### Example user template
+
+# IntelliJ project files
+.idea
+*.iml
+out
+gen
+node_modules/
+.idea/

README.md

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 # assignment_async_nodejs
 Async Node.js sprint
+
+Jennifer Louie

data/lorem.txt

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+Lorem ipsum dolor sit amet, consectetur adipiscing elit. Morbi eget libero et ligula volutpat gravida. Nam venenatis ante nisl, id imperdiet enim imperdiet nec. Quisque cursus hendrerit erat, nec molestie libero fringilla nec. Aliquam varius condimentum nisl, in ullamcorper quam molestie eget. Sed eleifend massa tempor, dapibus magna sit amet, mattis est. Donec maximus rhoncus leo, ac suscipit risus facilisis at. Donec sollicitudin sapien nibh. Vivamus ut nisl finibus, pulvinar nisl vel, tincidunt tortor. Donec faucibus arcu vitae enim tincidunt posuere. Nunc ut dolor lectus. Duis vehicula aliquet tortor quis feugiat. Maecenas dignissim ipsum at pharetra volutpat. Vivamus non bibendum nibh, vel dictum neque. Proin id orci convallis, viverra urna vestibulum, sollicitudin orci. Duis congue augue lobortis, bibendum ante vel, pretium ligula. Duis faucibus justo non tempor cursus.

data/test.txt

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+Hello!Hello again!

emitter-test.js

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+const EventEmitter = require('./emitter');
+// const EventEmitter = require('events');
+
+const eventEmitter = new EventEmitter();
+
+const callback = () => {
+  console.log('an event occurred!');
+};
+
+eventEmitter.on('event', callback);
+eventEmitter.emit('event');
+
+eventEmitter.removeListener('event', callback);

emitter.js

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+const _ = require('lodash');
+
+const emitter = function() {
+
+  var eventListeners = [];
+
+  this.on = function(eventType, callback) {
+    var event = _.find(eventListeners, ['event', eventType]);
+    if(event) {
+      event.listeners.push(callback);
+    }
+    else {
+      eventListeners.push({
+        'event': eventType,
+        'listeners': [callback]
+      });
+    }
+  };
+
+  this.emit = function(eventType, args) {
+    var event = _.find(eventListeners, ['event', eventType]);
+    if(event) {
+      _.forEach(event.listeners, (callback) => {
+        _.attempt(callback, args);
+      });
+    }
+  };
+
+  this.removeListener = function(eventType, callback) {
+    var event = _.find(eventListeners, ['event', eventType]);
+    if(event) {
+      _.forEach(event.listeners, (listener) => {
+        if(_.isEqual(listener, callback)) {
+          const index = event.listeners.indexOf(listener);
+
+          if (index !== -1) {
+            event.listeners.splice(index, 1);
+          }
+          return false;  // break forEach
+        }
+      });
+    }
+  };
+
+  this.removeAllListeners = function(eventType) {
+    var event = _.find(eventListeners, ['event', eventType]);
+    if(event) {
+      event.listeners.length = 0;  // clear array
+    }
+  };
+};
+
+module.exports = emitter;

fsp-test.js

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+const fsp = require('./fsp');
+
+fsp.readFile('./data/lorem.txt')
+  .then(function(data) {
+    // Outputs the file data
+    console.log(data);
+  })
+  .catch(function(err) {
+    console.error(err);
+  });
+
+fsp.writeFile('./data/test.txt', 'Hello!')
+  .then(function(res) {
+    // Outputs the file data
+    // after writing
+    console.log(res);
+  })
+  .catch(function(err) {
+    console.error(err);
+  });
+
+fsp.appendFile('./data/test.txt', 'Hello again!')
+  .then(function(res) {
+    // Outputs the file data
+    // after appending
+    console.log(res);
+  })
+  .catch(function(err) {
+    console.error(err);
+  });

fsp.js

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+const fs = require('fs');
+
+const fsp = {
+  readFile: function(path) {
+    return new Promise((resolve, reject) => {
+      fs.readFile(path, 'utf8', (error, data) => {
+        if(error) {
+          reject(error);
+        }
+        resolve(data);
+      });
+    });
+  },
+
+  writeFile: function(file, data) {
+    return new Promise((resolve, reject) => {
+      fs.writeFile(file, data, (error) => {
+        if(error) {
+          reject(error);
+        }
+        resolve(data);
+      });
+    });
+  },
+
+  appendFile: function(file, data) {
+    return new Promise((resolve, reject) => {
+      fs.appendFile(file, data, (error) => {
+        if(error) {
+          reject(error);
+        }
+        resolve(data);
+      });
+    });
+  },
+};
+
+module.exports = fsp;