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Angular Services

You're reading from   Angular Services -

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Product type Paperback
Published in Feb 2017
Publisher Packt
ISBN-13 9781785882616
Length 294 pages
Edition 1st Edition
Languages
Tools
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Toc

Table of Contents (9) Chapters Close

Preface 1. Setting Up the Environment 2. Introducing Wire-Frames FREE CHAPTER 3. The Collector Service - Using Controllers to Collect Data 4. The Rating Service - Data Management 5. The Notifier Service - Creating Cron Jobs in Angular 6. The Evidence Tree Builder Service - Implementing the Business Logic 7. The Report Generator Service - Creating Controllers to Set Report Template 8. The Accuracy Manager Service - Putting It All Together

Cron job versus Interval/Timeout


As you know, there are native JavaScript functions such as setInterval() or setTimeout(), which can run certain tasks periodically. But the main reason that they are not practical here is their limited lifespan. In other words, their life depends on the JavaScript host (mostly browsers) that executes them. Kill the browser process and they are long dead. This is not ideal, because we need a reliable process that runs in the background - possibly forever - and gathers news and sends emails without requiring to leave a browser window open 24/7.

For that reason, we need something on the system level and Cron jobs sound like a perfect choice for this matter. System administrators have been using them for decades and all we need is to run a command with a bunch of parameters inside a terminal window. With this solution, we can achieve our goal in three steps:

  1. First we need to generate a .js file so we can call it from the command line. We can continue creating TypeScript...

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