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ECMAScript Cookbook

You're reading from   ECMAScript Cookbook Over 70 recipes to help you learn the new ECMAScript (ES6/ES8) features and solve common JavaScript problems

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Product type Paperback
Published in Mar 2018
Publisher Packt
ISBN-13 9781788628174
Length 348 pages
Edition 1st Edition
Languages
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Author (1):
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Ross Harrison Ross Harrison
Author Profile Icon Ross Harrison
Ross Harrison
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Table of Contents (14) Chapters Close

Preface 1. Building with Modules FREE CHAPTER 2. Staying Compatible with Legacy Browsers 3. Working with Promises 4. Working with async/await and Functions 5. Web Workers, Shared Memory, and Atomics 6. Plain Objects 7. Creating Classes 8. Inheritance and Composition 9. Larger Structures with Design Patterns 10. Working with Arrays 11. Working with Maps and Symbols 12. Working with Sets 13. Other Books You May Enjoy

Using Array#every and Array#some to test array values


Sometimes, we need to know information about the array as a whole rather than individual elements, such as "Are there any elements that meet some criterion?" or "Do all the elements meet some criterion?".

In this recipe, we'll take a look at how to use the some and every methods to test an array.

Getting ready

This recipe assumes that you already have a workspace that allows you to create and run ES modules in your browser. If you don't, refer to the first two chapters.

How to do it...

  1. Open your command-line application, and navigate to your workspace.
  2. Create a new folder named 10-03-using-every-and-some-to-test-values.
  1. Create a main.js file that defines a new class named Rocket that takes a constructor argument name and assigns it to an instance property:
// main.js 
class Rocket { 
  constructor(name) { 
    this.name = name; 
  } 
   } 
  1. Create a main function that creates several Rocket instances and places them into an array:
// main.js 
export...
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