Comparing a value from two different array of objects in React.JS

Question

I am looking for a simple solution to compare just the "session" values from two different arrays of objects using React.JS.

I have:

  this.state = {
        dataOne: [
            {
                id: "1",
                session: "10:00",
                value: "10:00"
            },
            {
                id: "2",
                session: "10:15",
                value: "10:15"
            },
            {
                id: "3",
                session: "10:30",
                value: "10:30"
            },
            {
                id: "4",
                session: "10:45",
                value: "10:45"
            },
            {
                id: "5",
                session: "11:00",
                value: "11:00"
            },
        ],
        dataTwo: [
            {
                id: "6",
                session: "10:00",
                value: "10:00"
            },
            {
                id: "7",
                session: "10:15",
                value: "10:15"
            },
            {
                id: "8",
                session: "11:30",
                value: "11:30"
            },
            {
                id: "9",
                session: "12:45",
                value: "12:45"
            },
            {
                id: "10",
                session: "13:00",
                value: "13:00"
            },
        ]
    }
}

Those are the two arrays I need to compare.

I tried the following thing:

 if(this.state.dataOne.map(item => item.session) === (this.state.dataTwo.some(item => item.session)) {
       return console.log('true');
 else {
       return console.log('false);
  }

Any suggestions? It always returns false to me....

Are you trying to compare each session of dataOne with the corresponding index session in the second array? — adiga
– adiga, Commented Jul 20, 2020 at 12:16
I don't really know what exact you want to compare. Probably it can work for you: dataOne.map(item => item.session).sort().join('') === dataTwo.map(item => item.session).sort().join('') — Ramil Garipov
– Ramil Garipov, Commented Jul 20, 2020 at 12:18
Compare them how? You said you want to compare them, but that's pretty vague. You can compare them in a hundred different ways. — TKoL
– TKoL, Commented Jul 20, 2020 at 12:19

Rajaprabhu Aravindasamy · Accepted Answer · 2020-07-20 12:20:17Z

1

Array.prototype.map will return an object(array) and Array.prototype.some will return a boolean. Since you are using a strict equal, the expression will always be evaluated to false

const dataOneSession = this.state.dataOne.map(item => item.session);
const dataTwoSession = this.state.dataTwo.map(item => item.session);

let isAllValueMatched = true;

dataOneSession.forEach((value, i) => {
  if(value !== dataTwoSession[i]) {
    isAllValueMatched = false;
  }
});

if(isAllValueMatched) console.log(true);
else console.log(false);

I just corrected the code that you had given, we can write this code in an optimised way if you furnish more information like, are the arrays going to be in same length, will there be a dataThree? etc.

edited Jul 20, 2020 at 12:20

answered Jul 20, 2020 at 12:14

Rajaprabhu Aravindasamy

67.2k17 gold badges107 silver badges133 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

Ramil Garipov Over a year ago

It possible without extra map. And some performance optimisations: const isAllValueMatched = dataOne.every(({session}, i) => session === dataTwo[i].session)

Rajaprabhu Aravindasamy Over a year ago

Yeah I agree. But cannot give such solutions without knowing, dataTwo gonna be the same size as dataOne. no? Could be resulted in an exception. OP has to comment on it.

Valentin Georgiev Over a year ago

The initial idea is that i need to check if one session from the first array is equal to a session in second array.

Ramil Garipov Over a year ago

Yes, you are right. If arrays' length aren't equal, there's no reason to check them:

const isAllValueMatched = dataOne.length === dataTwo.length && dataOne.every(({session}, i) => session === dataTwo[i].session)

Collectives™ on Stack Overflow

Comparing a value from two different array of objects in React.JS

1 Answer 1

4 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

4 Comments

Your Answer

Sign up or log in

Post as a guest

Related