javascript - How to merge two arrays of objects by ID using lodash?

Question

(This question already has answers here): question from:https://stackoverflow.com/questions/38612972/how-to-merge-two-arrays-of-objects-by-id-using-lodash

Answer 1

If both arrays are in the correct order; where each item corresponds to its associated member identifier then you can simply use.

var merge = _.merge(arr1, arr2);

Which is the short version of:

var merge = _.chain(arr1).zip(arr2).map(function(item) {
    return _.merge.apply(null, item);
}).value();

Or, if the data in the arrays is not in any particular order, you can look up the associated item by the member value.

var merge = _.map(arr1, function(item) {
    return _.merge(item, _.find(arr2, { 'member' : item.member }));
});

You can easily convert this to a mixin. See the example below:

_.mixin({
  'mergeByKey' : function(arr1, arr2, key) {
    var criteria = {};
    criteria[key] = null;
    return _.map(arr1, function(item) {
      criteria[key] = item[key];
      return _.merge(item, _.find(arr2, criteria));
    });
  }
});

var arr1 = [{
  "member": 'ObjectId("57989cbe54cf5d2ce83ff9d6")',
  "bank": 'ObjectId("575b052ca6f66a5732749ecc")',
  "country": 'ObjectId("575b0523a6f66a5732749ecb")'
}, {
  "member": 'ObjectId("57989cbe54cf5d2ce83ff9d8")',
  "bank": 'ObjectId("575b052ca6f66a5732749ecc")',
  "country": 'ObjectId("575b0523a6f66a5732749ecb")'
}];

var arr2 = [{
  "member": 'ObjectId("57989cbe54cf5d2ce83ff9d8")',
  "name": 'yyyyyyyyyy',
  "age": 26
}, {
  "member": 'ObjectId("57989cbe54cf5d2ce83ff9d6")',
  "name": 'xxxxxx',
  "age": 25
}];

var arr3 = _.mergeByKey(arr1, arr2, 'member');

document.body.innerHTML = JSON.stringify(arr3, null, 4);

body { font-family: monospace; white-space: pre; }

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