CODEWITHSUNDEEP
javascriptarraysjsonindexingmatch
Aoguzie
Aoguzie

Reputation: 35

Lookup matching array oject properties

I have two arrays:

var scores = [{ name: "Bob", score: 19 }, { name: "Harry", score: 27 }, { name: "Janelle", score: 35 }];

var ranks = [{ name: "Bob", rank: 3 }, { name: "Harry", rank: 2 }, { name: "Janelle", rank: 1 }];

I want to merge the two arrays and add "rank" to all the corresponding arrays without repeating "name". Just like INDEX MATCH in Excel.

Upvotes: 0

Views: 30

Answers (2)

Siva Kondapi Venkata
Siva Kondapi Venkata

Reputation: 11001

Go thru both arrays and build one object with keys as unique name and accumulate values. Use Object.values to values as an array.

var scores = [
  { name: "Bob", score: 19 },
  { name: "Harry", score: 27 },
  { name: "Janelle", score: 35 }
];

var ranks = [
  { name: "Bob", rank: 3 },
  { name: "Harry", rank: 2 },
  { name: "Janelle", rank: 1 }
];

const merge = (arr1, arr2) => {
  const res = {};
  [...arr1, ...arr2].forEach(item =>
    Object.assign(res, { [item.name]: { ...res[item.name], ...item } })
  );
  return Object.values(res);
};

console.log(merge(scores, ranks));

Upvotes: 0

Miaplacidus
Miaplacidus

Reputation: 545

You can create a function named mergeArrays that accepts the source array, the destination array, and a key to match array items with. Using Array.map iterate through the source array, then when a destination array item with the same key value is found, assign the object's values and return the map. Note that this will not only assign rank to the source array, but all the values in the destination array. Seeming as how in the example rank is the only differing property it should not be a problem.

Repl Example

var scores = [
  { name: "Bob", score: 19 }, 
  { name: "Harry", score: 27 }, 
  { name: "Janelle", score: 35 }
]

var ranks = [
  { name: "Bob", rank: 3 }, 
  { name: "Harry", rank: 2 }, 
  { name: "Janelle", rank: 1 }
]

const mergeArrays = (source, destination, key) => {
  return scores.map((score) => {
    let rank = ranks.find((rank) => rank[key] === score[key])
    return Object.assign(score, rank)
  })
}

console.log(mergeArrays(scores, ranks, 'name'))

Upvotes: 1

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