Merging 2 arrays with different size by the same value of their keys in javascript-CodePudding

Can I merge 2 arrays with the same value of the same key? Already tried using map.set() but it wont work on my end.

const errArray = [
 { 'id': 1, 'error': ["Error 1", "Error2"] }
 { 'id': 2, 'error': ["Error 3", "Error4"] }
]

const warnArray = [
 { 'id': 1, 'warning': ["Error 5", "Error6"]}
]

I want to have a result of :

[
 { 'id': 1, 
   'error': ["Error 1", "Error2"],
   'warning': ["Error 5", "Error6"]
 }, {
   'id': 2,
   'error': ["Error 3", "Error4]
 }
]

CodePudding user response：

You first concat them into one array. Then group by id, extending into each other those who match by id. Then finally flatten the object into array.

const errArray = [{
    'id': 1,
    'error': ["Error 1", "Error2"]
  },
  {
    'id': 2,
    'error': ["Error 3", "Error4"]
  }
]

const warnArray = [{
  'id': 1,
  'warning': ["Error 5", "Error6"]
}]

var combined = errArray.concat(warnArray)


var result = Object.values(combined.reduce(function(agg, value) {
  agg[value.id] = Object.assign({}, value, agg[value.id]);
  return agg;
}, {}));


console.log(result)

CodePudding user response：

const errArray = [
    { 'id': 1, 'error': ["Error 1", "Error2"] },
    { 'id': 2, 'error': ["Error 3", "Error4"] }]

const warnArray = [
    { 'id': 1, 'warning': ["Error 5", "Error6"]},
    { 'id': 2, 'warning': ["Error 5", "Error6"]},
    { 'id': 3, 'warning': ["Error 5", "Error6"]}
]

let merged = []

if(errArray.length > warnArray.length){
    merged = errArray.map((item, i) => Object.assign({}, item, warnArray[i]));
}
else{
    merged = warnArray.map((item, i) => Object.assign({}, item, errArray[i]));
}

console.log(merged);

CodePudding user response：

Here is the implementation using the map:

const errArray = [
 { 'id': 1, 'error': ["Error 1", "Error2"] },
 { 'id': 2, 'error': ["Error 3", "Error4"] }
]

const warnArray = [
 { 'id': 1, 'warning': ["Error 5", "Error6"]}
]

const myMap = new Map();
errArray.forEach(err => {
    myMap.set(err.id, err);
});


warnArray.forEach(warn => {
    if(!myMap.has(warn.id)) {
        myMap.set(warn.id, warn);
    }
    else {
// You might want to do better merging than this, if the objects are complex
        const mergedObj = Object.assign({}, myMap.get(warn.id), warn);
        myMap.set(warn.id, mergedObj)
    }
});

const resultArr = Array.from(myMap.values());

console.log(resultArr)

CodePudding user response：

You can make an array of unique id by mapping each array to its id and creating a spread Set of them with [...new Set(Array)]. Then you can map each key to a combined object with Object.assign() and array.find():

const errArray = [
  { 'id': 1, 'error': ["Error 1", "Error2"] },
  { 'id': 2, 'error': ["Error 3", "Error4"] }
 ]
 
 const warnArray = [
  { 'id': 1, 'warning': ["Error 5", "Error6"]}
 ]

const keys = [
  ...new Set([
    ...errArray.map((v) => v.id), // [1, 2]
    ...warnArray.map((v) => v.id) // [1]
  ]),
];   //  keys = [1, 2]

const combined = keys.map((key) =>
  Object.assign({},
    errArray.find((v) => v.id === key),
    warnArray.find((v) => v.id === key)
  )
);

console.log(combined)