Using lodash what is a good way of mapping data from arrays into a single array?

Question

What is a fast way of mapping data like the data below using lodash into a single array of level2 objects.

    SomeObject = {
    name: 'someObject',
    level1: [
        {
            id: '1',
            level2: [
                { someValue: 'example1'},
                { someValue: 'example2'},
                { someValue: 'example3'},
                { someValue: 'example4'}
            ]
        },
        {
            id: '2',
            level2: [
                { someValue: 'example5' },
                { someValue: 'example6' },
                { someValue: 'example7' },
                { someValue: 'example8' }
            ]
        },
        {
            id: 'n',
            level2: [
                { someValue: 'examplen' },
            ]
        }
    ]
}

output:

[
 'example1',
 'example2',
 'example3',
 'example4',
 'example5',
 'example6',
 'example7',
 'example8',
 'examplen',
]

ignore: Stackflow is smarter than I so I have to type more non code stuff for it to stop complaining. So I'll type more so that I may post.

MrFlick · Accepted Answer · 2016-03-10 23:49:37Z

3

You can use flatMap() to collect all the "level2" arrays into a single array and then extract the "someValue" properties with a simple map()

_.map(_.flatMap(SomeObject.level1, "level2"),"someValue")

edited Mar 10, 2016 at 23:49

answered Mar 10, 2016 at 21:53

MrFlick

209k19 gold badges300 silver badges324 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

Calvin Over a year ago

My output was wrong and its been edited to the correct output. Sorry for the confusion! ugh its supposed to be an array of strings.

MrFlick Over a year ago

Then just add another map() to extract the someValue property.

Calvin Over a year ago

That'll create an array of arrays and then flatten handles it. Genius. Thank you

MrFlick Over a year ago

@Calvin Now that i'm back at my computer, i've updated the answer to use flatMap. That basically does both the map and flatten

Collectives™ on Stack Overflow

Using lodash what is a good way of mapping data from arrays into a single array?

1 Answer 1

4 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

4 Comments

Your Answer

Sign up or log in

Post as a guest

Related