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  • Book Overview & Buying Lo-Dash Essentials
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Lo-Dash Essentials

Lo-Dash Essentials

By : Adam Boduch
4.8 (8)
Buy this Book
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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)
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Preface
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Preface
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What this book covers
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What you need for this book
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Who this book is for
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Conventions
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Reader feedback
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Customer support
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1
1. Working with Arrays and Collections
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1. Working with Arrays and Collections
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The difference between arrays and collections
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Iterating over collections
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Sorting data
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Searching for data
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Slicing collections into smaller pieces
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Transforming collections
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Summary
2
2. Working with Objects
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2. Working with Objects
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Determining an object type
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Assigning and accessing properties
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Iterating over objects
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Calling methods
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Transforming objects
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Creating and cloning objects
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Summary
3
3. Working with Functions
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3. Working with Functions
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Binding function contexts
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Decorating functions
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Function constraints
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Timed execution
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Composing and currying functions
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Summary
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4. Transformations Using Map/Reduce
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4. Transformations Using Map/Reduce
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Plucking values
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Mapping collections
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Mapping objects
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Reducing collections
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Reducing objects
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Binding contexts
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Map/reduce patterns
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Summary
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5. Assembling Chains
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5. Assembling Chains
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Creating Lo-Dash wrappers
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Building filters
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Testing truth conditions
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Counting items
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Transformations
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Intermediary results
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Keys and values
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Returning wrappers
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Summary
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6. Application Building Blocks
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6. Application Building Blocks
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Generic functions
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Generic wrappers and chains
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Composing functions
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Creating mixins
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Summary
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7. Using Lo-Dash with Other Libraries
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7. Using Lo-Dash with Other Libraries
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Modules
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jQuery
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Backbone
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Node.js
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Summary
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8. Internal Design and Performance
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8. Internal Design and Performance
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Design principles
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Improving performance
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Lazy evaluation
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Caching things
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Summary
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Index
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Index

Determining an object type

In this section, we'll look at how type validation is typically handled in JavaScript and how the type-checking functions in Lo-Dash improve the situation.

Type coercion

Type coercion happens in JavaScript when one object is compared to another. That is, we have one object operand, the operator, and the second object operand. Depending on the operation being performed, the second object might be coerced into a representation that is compatible with the first operand. Take the following operation, for example:

true == 1

These are obviously different objects representing different primitive types. In the spirit of loosely typed programming, this expression triggers type coercion. The first operator is a Boolean value and the second operator is a number. The == equality operator will take the Boolean representation of 1 and compare it with true. This is why, this expression always evaluates to true. The values are roughly equal.

You can avoid type coercion using the strict...

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Tech Concepts
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Programming languages
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