I have 2 arrays like below:
const array1 = [{name: "1"}, {name: "2"}, {name: "3"}, {name: "4"}, {name: "4"}];
const array2 = [{name: "1"}, {name: "5"}, {name: "3"}, {name: "4"}, {name: "4"}, {name: "4"}, {name: "1"}, {name: "1"}, {name: "2"}];
Expected Output is:
[{name: "1"}, {name: "2"}, {name: "3"}, {name: "4"}, {name: "4"}, {name: "5"}, {name: "4"}, {name: "1"}, {name: "1"}];
The result array should contain the array1's all elements and those elements from array2 that are not already present in array1
I tried using _.unionBy
_.unionBy(array1, array2, 'name')
but it only results an array with uniq 'name'
How can we achieve that using lodash?
You can use unionBy (lodash)
let result = _.unionBy(array1 , array2, 'name');
unionBy - https://docs-lodash.com/v4/union-by/
Assuming you do not want { name: "2" } as last item of the result set, you could count the grouped items and add wanted items.
const
array1 = [{ name: "1" }, { name: "2" }, { name: "3" }, { name: "4" }, { name: "4" }],
array2 = [{ name: "1" }, { name: "5" }, { name: "3" }, { name: "4" }, { name: "4"}, { name: "4" }, { name: "1" }, { name: "1" }, { name: "2" }],
counts = {},
result = array1.map(o => (counts[o.name] = (counts[o.name] || 0) + 1, o));
result.push(...array2.filter(o => !counts[o.name] || !counts[o.name]--));
console.log(result);.as-console-wrapper { max-height: 100% !important; top: 0; }