CODEWITHSUNDEEP
javascriptarraysobjectconcatenation
RamAlx
RamAlx

Reputation: 7334

Concat n numbers of array into a single array

Suppose i have an object whose values are arrays just like this:

obj = {
    'key1': [1,2],
    'key2': [3,4],
    'key3': [5,6],
}

How to i merge all the arrays of the object into one using concat. The number of keys of the object is dynamic of course but it will have at least one instance The desired output is this:

[1,2,3,4,5,6]

Upvotes: 2

Views: 173

Answers (3)

Yevhen Horbunkov
Yevhen Horbunkov

Reputation: 15530

flat() on Object.values() is supposed to do the job:

const obj = {
        key1: [1,2],
        key2: [3,4],
        key3: [5,6]
      },
      merged = Object.values(obj).flat()

console.log(merged)
.as-console-wrapper{min-height:100%}

If being unlucky enough to deal with IE or Edge, one may fallback to reduce() for flattening:

const obj = {
        key1: [1,2],
        key2: [3,4],
        key3: [5,6]
      },
      merged = Object.keys(obj).reduce(function(r,k){     
        return r.concat(obj[k])
      }, [])

console.log(merged)
.as-console-wrapper{min-height:100%}

Upvotes: 9

jtwalters
jtwalters

Reputation: 1134

If you assume all the values of the object will an array you can make a Object.values() loop and concat each array.

const obj={
    'key1': [1,2],
    'key2': [3,4],
    'key3': [5,6],
};

const res = [];
for (const value of Object.values(obj)) {
    res.push(...value);
}
/// res: [1,2,3,4,5,6]

Upvotes: 2

Mathew Berg
Mathew Berg

Reputation: 28750

var obj={ 'key1': [1,2], 'key2': [3,4], 'key3': [5,6] };

var result = Object.values(obj)
    .reduce((accum, values) => {
        accum.push(...values);
        return accum;
    }, []);

console.log(result);

Upvotes: 4

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