Improve Your App's Search Results with Auto-Tuning

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[{
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		"session_id": "1",
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		"event_id": "search_query",
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		"metadata": {
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			"search_value": "romanian food"
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		},
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		"timestamp": "1"
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	},
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	{
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		"session_id": "1",
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		"event_id": "add_to_cart",
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		"product_category":"eastern european cuisine",
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		"timestamp": "2"
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	},
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	{
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		"session_id": "1",
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		"event_id": "checkout",
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		"timestamp": "3"
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	},
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	{
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		"session_id": "1",
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		"event_id": "payment_success",
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		"timestamp": "4"
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	},
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	{
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		"session_id": "2",
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		"event_id": "search_query",
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		"metadata": {
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			"search_value": "hungarian food"
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		},
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		"timestamp": "1"
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	},
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	{
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		"session_id": "2",
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		"event_id": "add_to_cart",
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		"product_category":"eastern european cuisine",
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		"timestamp": "2"
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	}
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]

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[
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    # first we sort by timestamp to get everything in the correct sequence of events,
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    # as that is what we'll be using to draw logical correlations
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    {
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        '$sort': {
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            'timestamp': 1
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        }
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    },
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    # next, we'll group by a unique session_id, include all the corresponding events, and begin
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    # the filter for determining if a search_query exists
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    {
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        '$group': {
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            '_id': '$session_id',
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            'events': {
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                '$push': '$$ROOT'
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            },
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            'isSearchQueryPresent': {
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                '$sum': {
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                    '$cond': [
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                        {
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                            '$eq': [
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                                '$event_id', 'search_query'
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                            ]
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                        }, 1, 0
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                    ]
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                }
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            }
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        }
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    },
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    # we hide session_ids where there is no search query
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    # then create a new field, an array called searchQuery, which we'll use to parse
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    {
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        '$match': {
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            'isSearchQueryPresent': {
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                '$gte': 1
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            }
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        }
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    },
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    {
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        '$unset': 'isSearchQueryPresent'
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    },
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    {
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        '$set': {
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            'searchQuery': '$events.metadata.search_value'
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        }
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    }
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]

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[
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  {
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    "session_id": "1",
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    "events": [
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      {
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        "event_id": "search_query",
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        "search_value": "romanian food"
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      },
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      {
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        "event_id": "add_to_cart",
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        "context": {
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          "cuisine": "eastern european cuisine"
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        }
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      },
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      {
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        "event_id": "checkout"
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      },
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      {
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        "event_id": "payment_success"
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      }
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    ],
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    "searchQuery": "romanian food"
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  }, {
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    "session_id": "2",
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    "events": [
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      {
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        "event_id": "search_query",
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        "search_value": "hungarian food"
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      },
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      {
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        "event_id": "add_to_cart",
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        "context": {
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          "cuisine": "eastern european cuisine"
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        }
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      },
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      {
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        "event_id": "checkout"
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      }
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    ],
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    "searchQuery": "hungarian food"
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  },
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  {
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    "session_id": "3",
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    "events": [
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      {
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        "event_id": "search_query",
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        "search_value": "italian food"
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      },
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      {
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        "event_id": "add_to_cart",
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        "context": {
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          "cuisine": "western european cuisine"
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        }
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      }
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    ],
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    "searchQuery": "sad food"
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  }
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]

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// Provide a success indicator to determine which session we want to
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// compare any incomplete sessions with
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const successIndicator = "payment_success"
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//  what percentage similarity between two sets of click/event streams
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//  we'd accept to be determined as similar enough to produce a synonym
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//  relationship
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const acceptedConfidence = .9
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//  boost the confidence score when the following values are present
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//  in the eventstream
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const eventBoosts = {
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  successIndicator: .1
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}
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/**
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 * Enrich sessions with a flattened event list to make comparison easier.
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 * Determine if the session is to be considered successful based on the success indicator.
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 * @param {*} eventList List of events in a session.
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 * @returns {any} Calculated values used to determine if an incomplete session is considered to
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 * be related to a successful session.
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 */
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const enrichEvents = (eventList) => {
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  return {
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    eventSequence: eventList.map(event => { return event.event_id }).join(';'),
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    isSuccessful: eventList.some(event => { return event.event_id === successIndicator })
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  }
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}
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/**
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 * De-duplicate common tokens in two strings
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 * @param {*} str1
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 * @param {*} str2
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 * @returns Returns an array with the provided strings with the common tokens removed
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 */
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const dedupTokens = (str1, str2) => {
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  const splitToken = ' '
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  const tokens1 = str1.split(splitToken)
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  const tokens2 = str2.split(splitToken)
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  const dupedTokens = tokens1.filter(token => { return tokens2.includes(token)});
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  const dedupedStr1 = tokens1.filter(token => { return !dupedTokens.includes(token)});
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  const dedupedStr2 = tokens2.filter(token => { return !dupedTokens.includes(token)});
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  return [ dedupedStr1.join(splitToken), dedupedStr2.join(splitToken) ]
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}
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const findMatchingIndex = (synonyms, results) => {
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  let matchIndex = -1
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  for(let i = 0; i < results.length; i++) {
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    for(const synonym of synonyms) {
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      if(results[i].synonyms.includes(synonym)){
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        matchIndex = i;
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        break;
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      }
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    }
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  }
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  return matchIndex;
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}
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/**
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 * Inspect the context of two matching sessions.
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 * @param {*} successfulSession
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 * @param {*} incompleteSession
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 */
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const processMatch = (successfulSession, incompleteSession, results) => {
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  console.log(`=====\nINSPECTING POTENTIAL MATCH: ${ successfulSession.searchQuery} = ${incompleteSession.searchQuery}`);
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  let contextMatch = true;
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  // At this point we can assume that the sequence of events is the same, so we can
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  // use the same index when comparing events
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  for(let i = 0; i < incompleteSession.events.length; i++) {
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    // if we have a context, let's compare the kv pairs in the context of
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    // the incomplete session with the successful session
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    if(incompleteSession.events[i].context){
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      const eventWithContext = incompleteSession.events[i]
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      const contextKeys = Object.keys(eventWithContext.context)
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      try {
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        for(const key of contextKeys) {
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          if(successfulSession.events[i].context[key] !== eventWithContext.context[key]){
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            // context is not the same, not a match, let's get out of here
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            contextMatch = false
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            break;
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          }
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         }
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      } catch (error) {
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        contextMatch = false;
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        console.log(`Something happened, probably successful session didn't have a context for an event.`);
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      }
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    }
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  }
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  // Update results
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  if(contextMatch){
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    console.log(`VALIDATED`);
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    const synonyms = dedupTokens(successfulSession.searchQuery, incompleteSession.searchQuery, true)
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    const existingMatchingResultIndex = findMatchingIndex(synonyms, results)
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    if(existingMatchingResultIndex >= 0){
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      const synonymSet = new Set([...synonyms, ...results[existingMatchingResultIndex].synonyms])
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      results[existingMatchingResultIndex].synonyms = Array.from(synonymSet)
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    }
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    else{
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      const result = {
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        "mappingType": "equivalent",
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        "synonyms": synonyms
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      }
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      results.push(result)
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    }
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  }
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  else{
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    console.log(`NOT A MATCH`);
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  }
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  return results;
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}
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/**
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 * Compare the event sequence of incomplete and successful sessions
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 * @param {*} successfulSessions
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 * @param {*} incompleteSessions
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 * @returns
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 */
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const compareLists = (successfulSessions, incompleteSessions) => {
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  let results = []
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  for(const successfulSession of successfulSessions) {
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    for(const incompleteSession of incompleteSessions) {
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      // if the event sequence is the same, let's inspect these sessions
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      // to validate that they are a match
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      if(successfulSession.enrichments.eventSequence.includes(incompleteSession.enrichments.eventSequence)){
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        processMatch(successfulSession, incompleteSession, results)
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      }
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    }
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  }
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  return results
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}
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const processSessions = (sessions) => {
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  // console.log(`Processing the following list:`, JSON.stringify(sessions, null, 2));
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  // enrich sessions for processing
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  const enrichedSessions = sessions.map(session => {
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    return { ...session, enrichments: enrichEvents(session.events)}
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  })
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  // separate successful and incomplete sessions
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  const successfulEvents = enrichedSessions.filter(session => { return session.enrichments.isSuccessful})
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  const incompleteEvents = enrichedSessions.filter(session => { return !session.enrichments.isSuccessful})
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  return compareLists(successfulEvents, incompleteEvents);
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}
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/**
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 * Main Entry Point
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 */
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const main = () => {
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  const results = processSessions(eventsBySession);
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  console.log(`Results:`, results);
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}
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main();
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module.exports = processSessions;

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[
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    {
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        '$search': {
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            'index': 'synonym-search',
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            'text': {
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                'query': 'hungarian',
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                'path': 'cuisine-type'
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            },
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            'synonyms': 'similarCuisines'
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        }
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    }
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]