Browse Library
Sign In Start Free Trial
Close icon Search icon
Account
Browse Library Sign In Start Free Trial

Add to playlist

Create a Playlist

Modal Close icon
You need to login to use this feature.
  • Book Overview & Buying Lo-Dash Essentials
  • Table Of Contents Toc
Lo-Dash Essentials

Lo-Dash Essentials

By : Adam Boduch
4.8 (8)
Buy this Book
close
close
Lo-Dash Essentials

Lo-Dash Essentials

4.8 (8)
By: Adam Boduch
Buy this Book

Overview of this book

If you are a curious JavaScript developer interested simultaneously in tweaking the efficiency of your code, as well as improving the conciseness of it, and maintaining the readability of it, then this is the book for you. Ideally, the book is intended for readers already working on JavaScript projects and using frameworks such as jQuery and Backbone. Even if you're already using Lo-Dash, this book will show you how to use it efficiently. While extensive JavaScript experience isn't a requirement, you should have at least some prior programming experience in order to best understand the concepts presented.
Table of Contents (10 chapters)
close
close
close
Preface
Icon
Preface
Icon
What this book covers
Icon
What you need for this book
Icon
Who this book is for
Icon
Conventions
Icon
Reader feedback
Icon
Customer support
Lock Free Chapter
1
1. Working with Arrays and Collections
Icon
1. Working with Arrays and Collections
Icon
The difference between arrays and collections
Icon
Iterating over collections
Icon
Sorting data
Icon
Searching for data
Icon
Slicing collections into smaller pieces
Icon
Transforming collections
Icon
Summary
2
2. Working with Objects
Icon
2. Working with Objects
Icon
Determining an object type
Icon
Assigning and accessing properties
Icon
Iterating over objects
Icon
Calling methods
Icon
Transforming objects
Icon
Creating and cloning objects
Icon
Summary
3
3. Working with Functions
Icon
3. Working with Functions
Icon
Binding function contexts
Icon
Decorating functions
Icon
Function constraints
Icon
Timed execution
Icon
Composing and currying functions
Icon
Summary
4
4. Transformations Using Map/Reduce
chevron up
Icon
4. Transformations Using Map/Reduce
Icon
Plucking values
Icon
Mapping collections
Icon
Mapping objects
Icon
Reducing collections
Icon
Reducing objects
Icon
Binding contexts
Icon
Map/reduce patterns
Icon
Summary
5
5. Assembling Chains
Icon
5. Assembling Chains
Icon
Creating Lo-Dash wrappers
Icon
Building filters
Icon
Testing truth conditions
Icon
Counting items
Icon
Transformations
Icon
Intermediary results
Icon
Keys and values
Icon
Returning wrappers
Icon
Summary
6
6. Application Building Blocks
Icon
6. Application Building Blocks
Icon
Generic functions
Icon
Generic wrappers and chains
Icon
Composing functions
Icon
Creating mixins
Icon
Summary
7
7. Using Lo-Dash with Other Libraries
Icon
7. Using Lo-Dash with Other Libraries
Icon
Modules
Icon
jQuery
Icon
Backbone
Icon
Node.js
Icon
Summary
8
8. Internal Design and Performance
Icon
8. Internal Design and Performance
Icon
Design principles
Icon
Improving performance
Icon
Lazy evaluation
Icon
Caching things
Icon
Summary
9
Index
Icon
Index

Reducing objects

In this section, we will turn our attention to reducing objects and working with object accumulators. Reducing objects is a lot like reducing arrays, the difference being that you have a key instead of an index. Oh yeah, there's also the ordering, which is kind of important—arrays are ordered, objects aren't.

Previously in the chapter, we caught a glimpse of what accumulators are. Here we'll take a deeper look at object accumulators, including some of the built-in Lo-Dash functions that utilize this concept.

Reducing keys

You can reduce an object to something different based solely on its keys. For example, if there are only certain properties you need, you can reduce the object to include only those properties, using the following code:

var object = { 
        first: 'Kerry',
        last: 'Singleton',
        age: 41
    },  
    allowed = [ 'first', 'last' ];

_.reduce(object, function(result, value, key) {
    if (_.contains(allowed, key)) {
        result[key] = value;...
CONTINUE READING
83
Tech Concepts
36
Programming languages
73
Tech Tools
Icon Unlimited access to the largest independent learning library in tech of over 8,000 expert-authored tech books and videos.
Icon Innovative learning tools, including AI book assistants, code context explainers, and text-to-speech.
Icon 50+ new titles added per month and exclusive early access to books as they are being written.
Lo-Dash Essentials
End of Chapter 4
Next Chapter
notes
bookmark Notes and Bookmarks search Search in title playlist Add to playlist font-size Font size

Change the font size

margin-width Margin width

Change margin width

day-mode Day/Sepia/Night Modes

Change background colour

Close icon Search
Country selected
Close icon Your notes and bookmarks

Confirmation

Modal Close icon
claim successful
Order Page Read Now

Buy this book with your credits?

Modal Close icon
Are you sure you want to buy this book with one of your credits?
Close
YES, BUY

Submit Your Feedback

Modal Close icon
Modal Close icon
Modal Close icon