Set same value of given property for all objects within array and eliminate duplicates

Question

I have this object of objects:

{
  "0": {
    "boardingGate": "exit_0",
    "departureTerminal": "1",
    "terminalArea": 0,
    "arrivalGate": "enter_0",
    "arrivalTerminal": "2",
    "terminalArea": 0
  },
  "1": {
    "boardingGate": "exit_1",
    "departureTerminal": "1",
    "terminalArea": 0,
    "arrivalGate": "enter_1",
    "arrivalTerminal": "2",
    "terminalArea": 0
  },
  "2": {
    "boardingGate": "exit_0",
    "departureTerminal": "1",
    "terminalArea": 0,
    "arrivalGate": "enter_0",
    "arrivalTerminal": "3",
    "terminalArea": 0
  },
  "3": {
    "boardingGate": "exit_1",
    "departureTerminal": "2",
    "terminalArea": 0,
    "arrivalGate": "enter_1",
    "arrivalTerminal": "3",
    "terminalArea": 0
  }
}

I need to change all "boardingGate" values to "exit_0" and all "arrivalGate" values to "enter_0". And once changed I need to remove the ones that give an equal object structure. The final resultant object I'm looking for would be the following:

{
  "0": {
    "boardingGate": "exit_0",
    "departureTerminal": "1",
    "terminalArea": 0,
    "arrivalGate": "enter_0",
    "arrivalTerminal": "2",
    "terminalArea": 0
  },
  "1": {
    "boardingGate": "exit_0",
    "departureTerminal": "1",
    "terminalArea": 0,
    "arrivalGate": "enter_0",
    "arrivalTerminal": "3",
    "terminalArea": 0
  },
  "2": {
    "boardingGate": "exit_0",
    "departureTerminal": "2",
    "terminalArea": 0,
    "arrivalGate": "enter_0",
    "arrivalTerminal": "3",
    "terminalArea": 0
  }
}

Eliminating in this case one of the first two that would obtain as final result the same data. I have tried with a forEach obtaining the Object.values(data) and I don't get the desired results... and I don't know if there would be an easier way either.

    const tickets = Object.values(data);

    tickets.forEach((next, index, ticket) => {
      const boardingGateKeys: any = Object.keys(next.boardingGate);
      const boardingGateValues: any = Object.values(next.boardingGate);

      boardingGateKeys.forEach((gate, gateIndex) => {
          const arrivalGateKeys: any = Object.keys(gate.outputs);
          const arrivalGateValues: any = Object.values(gate.outputs);
          arrivalGateValues.forEach((output, outputIndex) => {

              });
            }
        });
      });

Thank you very much for your help in advance

I have tried with a forEach obtaining the Object.values(data), could you please share the failed attempt? — Rajesh Dixit
– Rajesh Dixit, Commented Apr 28, 2020 at 8:53

Nina Scholz · Accepted Answer · 2020-04-28 09:11:10Z

1

You could get the entries, reduce the array by looking to the wanted vommon entries and add for unknown key/value pairs a new data set with updated properties.

Finally create an object from the array.

var data = { 0: { boardingGate: "exit_0", departureTerminal: "1", terminalArea: 0, arrivalGate: "enter_0", arrivalTerminal: "2" }, 1: { boardingGate: "exit_1", departureTerminal: "1", terminalArea: 0, arrivalGate: "enter_1", arrivalTerminal: "2" }, 2: { boardingGate: "exit_0", departureTerminal: "1", terminalArea: 0, arrivalGate: "enter_0", arrivalTerminal: "3" }, 3: { boardingGate: "exit_1", departureTerminal: "2", terminalArea: 0, arrivalGate: "enter_1", arrivalTerminal: "3" } },
    result = Object.assign({}, Object
        .values(data)
        .reduce((r, { boardingGate, arrivalGate, ...o }) => {
            const entries = Object.entries(o);
            if (!r.some(q => entries.every(([k, v]) => q[k] === v))) {
                r.push({ boardingGate: "exit_0", arrivalGate: "enter_0", ...o });
            }
            return r;
        }, [])
    );

console.log(data);

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answered Apr 28, 2020 at 9:11

Nina Scholz

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1 Comment

homerThinking Over a year ago

works perfectly !! now it's my turn to understand!! thank you very much

Yevhen Horbunkov · Accepted Answer · 2020-04-28 11:50:13Z

There are two concerns regarding your code:

the minor one (both of your input and expected objects are invalid due to duplicating terminalArea key)
and the major one - both of your attempt and accepted answer are implementing O(n²)-time algorithms (due to nested loops) which may cause huge performance loss (up to 90% slower compared to O(n)-time algorithm for 1k items), should your input be large enough

So, if you still consider something more comprehensive (and, what's more important, fast), please check out the following approach:

build up a hash map that contains unique combination of input object values
push remapped object (with uniformed values of boardingGate/arrivalGate) if its hash is missing from the hashmap

The proof of a concept is as follows:

const src = {"0":{"boardingGate":"exit_0","departureTerminal":"1","departureTerminalArea":0,"arrivalGate":"enter_0","arrivalTerminal":"2","arrivalTerminalArea":0},"1":{"boardingGate":"exit_1","departureTerminal":"1","departureTerminalArea":0,"arrivalGate":"enter_1","arrivalTerminal":"2","arrivalTerminalArea":0},"2":{"boardingGate":"exit_0","departureTerminal":"1","departureTerminalArea":0,"arrivalGate":"enter_0","arrivalTerminal":"3","arrivalTerminalArea":0},"3":{"boardingGate":"exit_1","departureTerminal":"2","departureTerminalArea":0,"arrivalGate":"enter_1","arrivalTerminal":"3","arrivalTerminalArea":0}},

      remapDedupe = input => {
        const hashMap = new Set(),
              result = []
        for(idx in input){
          const {boardingGate, arrivalGate, ...rest} = input[idx],
                hash = Object.values(rest).join('|')
          if(hashMap.has(hash)) continue               
          result.push({
            boardingGate: 'exit_0', 
            arrivalGate: 'enter_0', 
            ...rest
          })
          hashMap.add(hash)
        }
        return {...result}
      },
      
      result = remapDedupe(src)
        
console.log(result)

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