Applying multiple groupings using lodash - arrays

Question

I would like to group a JSON array by two properties (name and address2) and then reduce it. Here is the current JSON:
{
"clientId": "FOO",
"name": "John Doe",
"address1": "London",
"address2": "1 High Street",
"invoiceNumber": "1234",
"itemDescription": "Item 1",
"itemQuantity": 1
},
{
"clientId": "BAR",
"name": "John Doe",
"address1": "London",
"address2": "1 Oxford Street",
"invoiceNumber": "0987",
"itemDescription": "Item 2",
"itemQuantity": 1
},
{
"clientId": "FOO",
"name": "John Doe",
"address1": "London",
"address2": "1 High Street",
"invoiceNumber": "5678",
"itemDescription": "Item 3",
"itemQuantity": 1
}
This is what I would like to achieve:
[
{
"clientId": "FOO",
"name": "John Doe",
"address1": "London",
"address2": "1 High Street",
"deliveries": [
{
"invoiceNumber": "1234",
"itemQuantity": 1,
"itemDescription": "Item 1"
},
{
"invoiceNumber": "5678",
"itemDescription": "Item3",
"itemQuantity": 1
}
]
},
{
"clientId": "BAR",
"name": "JohnDoe",
"address1": "London",
"address2": "12 Oxford Street",
"deliveries": [
{
"invoiceNumber": "0987",
"itemDescription": "Item2",
"itemQuantity": 1
}
]
}
]
And here is the code that I have so far, which doesn't produce what I would hope it would:
var groups = _.groupBy(rows, function(value) {
return value.name + '#' + value.address2;
});
var data = _.map(groups, function(group) {
return {
clientId: group[0].clientId,
name: group[0].name,
address1: group[0].address1,
address2: group[0].address2,
deliveries: [{
invoiceNumber: _.map(group,'invoiceNumber'),
itemDescription: _.map(group,'itemDescription'),
itemQuantity: _.map(group,'itemQuantity'),
}]
}
});
And it produces the following output:
[ { clientId: 'FOO',
name: 'John Doe',
address1: 'London',
address2: '1 High Street',
deliveries: [ [Object] ] } ]
I am not sure how to create an array of "deliveries" objects within the lodash _.map function. Please help! :)

Answer 1

Use one map that picks out the properties you want from a group:
...
deliveries: _.map(group, item => _.pick(item, ['invoiceNumber', 'itemDescription', 'itemQuantity' ]))
...

Answer 2

You weren't far off!
Had a go at making it a little bit more succinct by using ES6 syntax and incorporating _.pick() into your code, as suggested by Gruff.
If you really like one-liners, that's possible, too! Lodash makes it easy to chain/nest functions to do this, although you may compromise some readability:
// Data:
const rows = [{
"clientId": "FOO",
"name": "John Doe",
"address1": "London",
"address2": "1 High Street",
"invoiceNumber": "1234",
"itemDescription": "Item 1",
"itemQuantity": 1
},
{
"clientId": "BAR",
"name": "John Doe",
"address1": "London",
"address2": "1 Oxford Street",
"invoiceNumber": "0987",
"itemDescription": "Item 2",
"itemQuantity": 1
},
{
"clientId": "FOO",
"name": "John Doe",
"address1": "London",
"address2": "1 High Street",
"invoiceNumber": "5678",
"itemDescription": "Item 3",
"itemQuantity": 1
}];
// Result:
const groups = _.groupBy(rows, item => item.clientId);
const result = _.map(groups, group => {
const {clientId, name, address1, address2} = group[0];
const deliveries = _.map(group, item => _.pick(item, ['invoiceNumber', 'itemDescription', 'itemQuantity']));
return {clientId, name, address1, address2, deliveries};
});
console.log('multi-liner result: ', result);
// One-line version:
const oneLiner = _.map(_.groupBy(rows, item => item.clientId), group => _.merge(_.pick(group[0], ['clientId', 'name', 'address1', 'address2']), {deliveries: _.map(group, item => _.pick(item, ['invoiceNumber', 'itemDescription', 'itemQuantity']))}));
console.log('one-liner result: ', oneLiner);
<script src="https://cdn.jsdelivr.net/lodash/4.17.1/lodash.min.js"></script>
Hope that helps! If you'd like more info on the Lodash functions used, here's the official documentation for them:
_.groupBy()
_.map()
_.pick()