有条件地从数组中删除重复项

Question

I have an array that looks like this

[
    {
        topic: 'Topic 1',
        person: { ... },
        unit: 'ABC-DEF'
    },
    {
        topic: 'Topic 1',
        person: { ... },
        unit: 'ABC'
    },
    {
        topic: 'Topic 1',
        person: { ... },
        unit: 'ABC-123-DEF'
    },
    {
        topic: 'Topic 2',
        person: { ... },
        unit: 'ABC-123'
    }
]

"units" are organisational units in my company. If there are duplicates by topic I want to keep only the object with the shortest unit and remove all others. So the example from above becomes:

[
    {
        topic: 'Topic 1',
        person: { ... },
        unit: 'ABC'
    },
    {
        topic: 'Topic 2',
        person: { ... },
        unit: 'ABC-123'
    }
]

I already took a look at uniqBy from lodash but how can I make sure that only the duplicate with the shortest unit stays in the array?

Answer 1

uniqBy保留找到的第一个项目，因此只需在过滤之前按unit.length排序：

_.uniqBy(_.sortBy(data, x => x.unit.length), 'topic')

Answer 2

Though this question is already answered, I tried it using native javascript APIs (in case someone wants to do it without using lodash)-

I used sort to sort the array according to shortest unit .

And then grouped them by topic and chose first item as item with shortest unit (because it was sorted in first step).

Checkout this code -

 var finalData = []; var data = [ { topic: 'Topic 1', person: { }, unit: 'ABC-DEF' }, { topic: 'Topic 1', person: { }, unit: 'ABC' }, { topic: 'Topic 1', person: { }, unit: 'ABC-123-DEF' }, { topic: 'Topic 2', person: { }, unit: 'ABC-123' } ]; data.sort((item1, item2) => { return item1.unit.length - item2.unit.length; }).reduce(function(groups, item) { if (!groups[item.topic]) { finalData.push(item); groups[item.topic] = true; } return groups; }, {}); console.log(finalData); 

I hope this helps :)