Merge pull request #81 from amos-ws16/feature-12_chat-text-comparison

Feature 12 chat text comparison

lib/plugins/chat-text-plugin.js

@@ -0,0 +1,32 @@
+const extractObject = require('../extract-object.js')
+const similarityPlugin = require('./similar-text-plugin.js')
+const meanAggregator = require('../aggregators/mean.js')
+const utils = require('../utils.js')
+
+/**
+ * Takes as an input an object of the form:
+ *
+ * @param chat - an object that is a chat
+ * @param text - an object that is a text
+ * @return score - between 1.0 and 0.0. This is the mean value of all the
+ * similarities between every single chat message and text.
+ */
+function chatComparisonPlugin (chat, text) {
+  let [messageText, e1] = extractObject(chat, 'chat[].text')
+  if ((e1 !== null) && (e1.constructor === Error)) {
+    throw new Error('Error extracting text from chat.')
+  }
+
+  utils.arrayNotEmpty(messageText)
+  utils.isValidString(text)
+  var singleMessageScores = []
+  for (let message of messageText) {
+    if ((message !== undefined) && (typeof (message) === 'string')) {
+      singleMessageScores.push(similarityPlugin(message, text))
+    }
+  }
+
+  return meanAggregator.create('*').eval(singleMessageScores)
+}
+
+module.exports = chatComparisonPlugin

lib/utils.js

@@ -177,4 +177,20 @@ function ensureValidAggregators (aggregators) {
   })
 }
 
-module.exports = { cloneObject, toDebugString, isValidString, isArray, isInRange, isInteger, isTimestamp, loadPlugin, loadModule, insertByPath, ensureValidAggregators }
+/**
+ * Throw an error if array is empty.
+ * @param array - the array to be checked
+ */
+function arrayNotEmpty (array) {
+  let count = 0
+  for (let a of array) {
+    if (a === undefined) {
+      count++
+    }
+  }
+  if (count === array.length) {
+    throw new Error('Array empty.')
+  }
+}
+
+module.exports = { cloneObject, toDebugString, isValidString, isArray, isInRange, isInteger, isTimestamp, loadPlugin, loadModule, insertByPath, ensureValidAggregators, arrayNotEmpty }

test/plugins/chat-text-plugin-test.js

@@ -0,0 +1,113 @@
+const buster = require('buster')
+const plugin = require('../../lib/plugins/chat-text-plugin.js')
+
+const testChat = {
+  chat: [
+    {
+      'type': 'message',
+      'text': 'Hello world'
+    },
+    {
+      'type': 'message',
+      'text': 'Hello underworld'
+    }
+  ]
+}
+
+const testChatSimple = {
+  chat: [
+    {
+      'type': 'message',
+      'text': 'Hello world'
+    }
+  ]
+}
+
+const brokenChat = {
+  chat: [
+    {
+      'type': 'message',
+      'notext': 1234
+    },
+    {
+      'type': 'message',
+      'notext': 'Hello underworld'
+    }
+  ]
+}
+
+const halfChat = {
+  chat: [
+    {
+      'type': 'message',
+      'notext': 1234
+    },
+    {
+      'type': 'message',
+      'text': 'Hello'
+    }
+  ]
+}
+
+const wrongeTypeChat = {
+  chat: [
+    {
+      'type': 'message',
+      'notext': 1234
+    },
+    {
+      'type': 'message',
+      'text': 'Hello'
+    }
+  ]
+}
+
+const extractObjectBroken = {
+  chat: 'chat value'
+}
+
+buster.testCase('Chat Scorer', {
+  'should throw error if chat': function () {
+    buster.assert.exception(() => plugin('', 'testphrase'))
+  },
+  'should throw error if no text to compare to': function () {
+    buster.assert.exception(() => plugin(testChat, ''))
+  },
+  'should throw error if no text in chat messages': function () {
+    buster.assert.exception(() => plugin(brokenChat, 'testphrase'))
+  },
+  'should throw error if chat messages cannot be extracted': function () {
+    buster.assert.exception(() => plugin(extractObjectBroken, 'Hello'))
+  },
+  'should ignore chat messages without text if others do have text': function () {
+    let result = plugin(halfChat, 'Hello')
+    buster.assert.equals(result, 1.0)
+  },
+  'should ignore chat messages without text': function () {
+    let result = plugin(wrongeTypeChat, 'Hello')
+    buster.assert.equals(result, 1.0)
+  },
+  'should throw error if second arg is not a valid string': function () {
+    buster.assert.exception(() => plugin(testChat, 1))
+  },
+  'should score 1 if chatmessage matches text': function () {
+    let compareText = testChatSimple.chat[0].text
+    let result = plugin(testChatSimple, compareText)
+    buster.assert.equals(result, 1.0)
+  },
+  'should score high if high similarity between messages and text': function () {
+    let compareText = 'Hello world'
+    let result = plugin(testChat, compareText)
+    buster.assert.near(result, 1.0, 0.3)
+  },
+  'should score medium if medium similarity between messages and text': function () {
+    let compareText = 'Hello'
+    let result = plugin(testChat, compareText)
+    buster.assert.near(result, 0.5, 0.3)
+  },
+  'should score low if low similarity between messages and text': function () {
+    let compareText = 'water'
+    let result = plugin(testChat, compareText)
+    buster.assert.near(result, 0.0, 0.2)
+  }
+})