I have two array with one common field member. how can I merge theme easily?
For example:
var arr1 = [{
"member" : ObjectId("57989cbe54cf5d2ce83ff9d6"),
"bank" : ObjectId("575b052ca6f66a5732749ecc"),
"country" : ObjectId("575b0523a6f66a5732749ecb")
},
{
"member" : ObjectId("57989cbe54cf5d2ce83ff9d8"),
"bank" : ObjectId("575b052ca6f66a5732749ecc"),
"country" : ObjectId("575b0523a6f66a5732749ecb")
}];
var arr2 = [{
"member" : ObjectId("57989cbe54cf5d2ce83ff9d6"),
"name" : 'xxxxxx',
"age" : 25
},
{
"member" : ObjectId("57989cbe54cf5d2ce83ff9d8"),
"name" : 'yyyyyyyyyy',
"age" : 26
}];
Expected:
var merge = [{
"member" : ObjectId("57989cbe54cf5d2ce83ff9d6"),
"bank" : ObjectId("575b052ca6f66a5732749ecc"),
"country" : ObjectId("575b0523a6f66a5732749ecb"),
"name" : 'xxxxxx',
"age" : 25
},
{
"member" : ObjectId("57989cbe54cf5d2ce83ff9d8"),
"bank" : ObjectId("575b052ca6f66a5732749ecc"),
"country" : ObjectId("575b0523a6f66a5732749ecb"),
"name" : 'yyyyyyyyyy',
"age" : 26
}];
I tried
var merge = _.unionBy(arr1, arr2, 'member');
but not merged as expected. shown array1 value. can any one help me?
This question is related to
javascript
lodash
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({_x000D_
'mergeByKey' : function(arr1, arr2, key) {_x000D_
var criteria = {};_x000D_
criteria[key] = null;_x000D_
return _.map(arr1, function(item) {_x000D_
criteria[key] = item[key];_x000D_
return _.merge(item, _.find(arr2, criteria));_x000D_
});_x000D_
}_x000D_
});_x000D_
_x000D_
var arr1 = [{_x000D_
"member": 'ObjectId("57989cbe54cf5d2ce83ff9d6")',_x000D_
"bank": 'ObjectId("575b052ca6f66a5732749ecc")',_x000D_
"country": 'ObjectId("575b0523a6f66a5732749ecb")'_x000D_
}, {_x000D_
"member": 'ObjectId("57989cbe54cf5d2ce83ff9d8")',_x000D_
"bank": 'ObjectId("575b052ca6f66a5732749ecc")',_x000D_
"country": 'ObjectId("575b0523a6f66a5732749ecb")'_x000D_
}];_x000D_
_x000D_
var arr2 = [{_x000D_
"member": 'ObjectId("57989cbe54cf5d2ce83ff9d8")',_x000D_
"name": 'yyyyyyyyyy',_x000D_
"age": 26_x000D_
}, {_x000D_
"member": 'ObjectId("57989cbe54cf5d2ce83ff9d6")',_x000D_
"name": 'xxxxxx',_x000D_
"age": 25_x000D_
}];_x000D_
_x000D_
var arr3 = _.mergeByKey(arr1, arr2, 'member');_x000D_
_x000D_
document.body.innerHTML = JSON.stringify(arr3, null, 4);
_x000D_
body { font-family: monospace; white-space: pre; }
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.14.0/lodash.min.js"></script>
_x000D_
Create dictionaries for both arrays using _.keyBy()
, merge the dictionaries, and convert the result to an array with _.values()
. In this way, the order of the arrays doesn't matter. In addition, it can also handle arrays of different length.
const ObjectId = (id) => id; // mock of ObjectId_x000D_
const arr1 = [{"member" : ObjectId("57989cbe54cf5d2ce83ff9d8"),"bank" : ObjectId("575b052ca6f66a5732749ecc"),"country" : ObjectId("575b0523a6f66a5732749ecb")},{"member" : ObjectId("57989cbe54cf5d2ce83ff9d6"),"bank" : ObjectId("575b052ca6f66a5732749ecc"),"country" : ObjectId("575b0523a6f66a5732749ecb")}];_x000D_
const arr2 = [{"member" : ObjectId("57989cbe54cf5d2ce83ff9d6"),"name" : 'xxxxxx',"age" : 25},{"member" : ObjectId("57989cbe54cf5d2ce83ff9d8"),"name" : 'yyyyyyyyyy',"age" : 26}];_x000D_
_x000D_
const merged = _(arr1) // start sequence_x000D_
.keyBy('member') // create a dictionary of the 1st array_x000D_
.merge(_.keyBy(arr2, 'member')) // create a dictionary of the 2nd array, and merge it to the 1st_x000D_
.values() // turn the combined dictionary to array_x000D_
.value(); // get the value (array) out of the sequence_x000D_
_x000D_
console.log(merged);
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.14.0/lodash.min.js"></script>
_x000D_
Using ES6 Map
Concat the arrays, and reduce the combined array to a Map. Use Object#assign to combine objects with the same member
to a new object, and store in map. Convert the map to an array with Map#values and spread:
const ObjectId = (id) => id; // mock of ObjectId_x000D_
const arr1 = [{"member" : ObjectId("57989cbe54cf5d2ce83ff9d8"),"bank" : ObjectId("575b052ca6f66a5732749ecc"),"country" : ObjectId("575b0523a6f66a5732749ecb")},{"member" : ObjectId("57989cbe54cf5d2ce83ff9d6"),"bank" : ObjectId("575b052ca6f66a5732749ecc"),"country" : ObjectId("575b0523a6f66a5732749ecb")}];_x000D_
const arr2 = [{"member" : ObjectId("57989cbe54cf5d2ce83ff9d6"),"name" : 'xxxxxx',"age" : 25},{"member" : ObjectId("57989cbe54cf5d2ce83ff9d8"),"name" : 'yyyyyyyyyy',"age" : 26}];_x000D_
_x000D_
const merged = [...arr1.concat(arr2).reduce((m, o) => _x000D_
m.set(o.member, Object.assign(m.get(o.member) || {}, o))_x000D_
, new Map()).values()];_x000D_
_x000D_
console.log(merged);
_x000D_
Source: Stackoverflow.com