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Mastering Immutable.js

You're reading from   Mastering Immutable.js Better JavaScript development using immutable data

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Product type Paperback
Published in Sep 2017
Publisher Packt
ISBN-13 9781788395113
Length 216 pages
Edition 1st Edition
Languages
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Author (1):
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Adam Boduch Adam Boduch
Author Profile Icon Adam Boduch
Adam Boduch
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Table of Contents (17) Chapters Close

Preface 1. Why Immutable.js? FREE CHAPTER 2. Creating Immutable Data 3. Persistent Changes 4. Filtering Collections and Finding Items 5. Sequences and Side-Effects 6. Sorting Collections 7. Mapping and Reducing 8. Zipping and Flattening 9. Persistent Change Detection 10. Working with Sets 11. Comparing Collections 12. Combining Collections 13. Declarative Decision Making 14. Side-Effects in User Interfaces 15. Side-Effects in Node.js 16. Immutable Architecture

Sorting lists of maps


You've seen how to use the sortBy() method to negate a value so that you can sort in descending order. The sortBy() method is also useful when you need to sort by more complex data and sort criteria. Even the sortBy() method has its limitations with respect to sorting lists of maps; so, you have to think about alternative approaches here.

The sortBy() method

The sortBy() method uses the default greater than and less than comparator function—the same default used by sort(). The function that is passed to sortBy() is called an iteratee, which is a function that's used to produce values that are fed into the comparator function. This is useful when you want to use the default comparator—writing iteratees is easier than customizing comparator functions.

Note

If it turns out that you've written an iteratee function and you have a reusable comparator function, you can use both. The sortBy() method accepts a comparator as its second argument.

Let's start by writing a simple utility...

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