Suppose, we have an array of objects like this −
const arr = [ { "customer": "Customer 1", "project": "1" }, { "customer": "Customer 2", "project": "2" }, { "customer": "Customer 2", "project": "3" } ]
We are required to write a JavaScript function that takes one such array, and yields (returns) a new array.
In the new array, all the customer keys with same values should be merged and the output should look something like this −
const output = [ { "Customer 1": { "projects": "1" } }, { "Customer 2": { "projects": [ "2", "3" ] } } ]
Example
Let us write the code −
const arr = [ { "customer": "Customer 1", "project": "1" }, { "customer": "Customer 2", "project": "2" }, { "customer": "Customer 2", "project": "3" } ] const groupCustomer = data => { const res = []; data.forEach(el => { let customer = res.filter(custom => { return el.customer === custom.customer; })[0]; if(customer){ customer.projects.push(el.project); }else{ res.push({ customer: el.customer, projects: [el.project] }); }; }); return res; }; console.log(groupCustomer(arr));
Output
And the output in the console will be −
[ { customer: 'Customer 1', projects: [ '1' ] }, { customer: 'Customer 2', projects: [ '2', '3' ] } ]