javascript - Select distinct objects from nested arrays using linq.js - Stack Overflow

Let's say I have the following data,

data: {
    variations: [{
        steps: [
            { Name: "Crawl", Status: "Complete" },
            { Name: "Walk", Status: "InProgress" }
        ]
    },{
        steps: [
            { Name: "Crawl", Status: "Complete" },
            { Name: "Walk", Status: "Complete" },
            { Name: "Run", Status: "NotStarted" }
        ]
    }]
}

How would I arrive at this set of data using linq.js? The resulting set of data is the unique steps across all variations. Notice, the duplicate Crawl is not in the result.

[
    { Name: "Crawl", Status: "Complete" },
    { Name: "Walk", Status: "InProgress" },
    { Name: "Walk", Status: "Complete" },
    { Name: "Run", Status: "NotStarted" }
]

I have tried many binations of Select and SelectMany, but I'm having no luck.

Let's say I have the following data,

data: {
    variations: [{
        steps: [
            { Name: "Crawl", Status: "Complete" },
            { Name: "Walk", Status: "InProgress" }
        ]
    },{
        steps: [
            { Name: "Crawl", Status: "Complete" },
            { Name: "Walk", Status: "Complete" },
            { Name: "Run", Status: "NotStarted" }
        ]
    }]
}

How would I arrive at this set of data using linq.js? The resulting set of data is the unique steps across all variations. Notice, the duplicate Crawl is not in the result.

[
    { Name: "Crawl", Status: "Complete" },
    { Name: "Walk", Status: "InProgress" },
    { Name: "Walk", Status: "Complete" },
    { Name: "Run", Status: "NotStarted" }
]

I have tried many binations of Select and SelectMany, but I'm having no luck.

• javascript
• linq.js

Share Improve this question Follow asked Apr 7, 2016 at 9:29 Scott LinScott Lin 1,56211 gold badge1919 silver badges3131 bronze badges

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1 Answer 1

Sorted by: Reset to default 4

First you'll need to flatten to an array of steps. Once you have that, you'll have to pick out the distinct copies of the steps. Since you're dealing with objects, you'll need to provide a parer. I would just bine the properties that make it distinct into a string.

var query = Enumerable.From(result.data.variations)
  .SelectMany("$.steps")
  .Distinct("[$.Name, $.Status].join(',')")
  .ToArray();