CODEWITHSUNDEEP
javascriptarraystypescriptobject
userMod2
userMod2

Reputation: 8970

Object.assign - merging arrays values

I have a function that returns an object like (key is string and value is array of strings):

{"myType1": ["123"]}

I want to merge all the results its returning for example - if I have:

{"myType1": ["123"]}

{"myType2": ["456"]}

{"myType1": ["789"]}

I'd like to get 

{"myType1": ["123", "789], "myType2": ["456"]}

I've seen Object.assign however that doesn't merge the values it just replaces with the most recent.

Has anyone got an examples of how I can achieve this?

Any help appreciated.

Thanks.

Upvotes: 1

Views: 144

Answers (3)

Cristián Ormazábal
Cristián Ormazábal

Reputation: 1532

Here is a one liner with the desired process:

Array.from(new Set([{"myType1": ["123"]}, {"myType2": ["456"]}, {"myType1": ["789"]}].map(item => Object.keys(item)[0]).sort())).map(e => { const entry = {}; entry[e] = items.filter(item => Object.keys(item)[0] === e).map(item => item[e][0]); return entry })

Result:

[ { myType1: [ '123', '789' ] }, { myType2: [ '456' ] } ]

Regards.

Upvotes: 0

Jack Bashford
Jack Bashford

Reputation: 44125

Make a function that adds each property to a result object, and call it with each object you get.

let res = {};

const addObj = obj => {
  Object.entries(obj).forEach(([k, v]) => (res[k] = res[k] || []).push(...v));
};

addObj({"myType1": ["123"]});
addObj({"myType2": ["456"]});
addObj({"myType1": ["789"]});

console.log(res);
.as-console-wrapper { max-height: 100% !important; top: auto; }

Upvotes: 0

Eddie
Eddie

Reputation: 26844

You can the keys of an object by using Object.keys. Use forEach to loop thru the keys and modify the result object.

var result = {};
function mergeObj(o) {
  Object.keys(o).forEach(k=>{
    result[k] = ( result[k] || [] ).concat(o[k]);
  })
}

mergeObj({"myType1": ["123"]});
mergeObj({"myType2": ["456"]});
mergeObj({"myType1": ["789"]});

console.log(result);

Upvotes: 2

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