It has been available for free on Amazon for a while. I downloaded it last night. If you prefer going the Amazon route and having it saved to your account:
Here are all the local Amazon links I could find:
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I'm learning Angular 5 from this free book, https://www.amazon.com/Angular-Practice-applications-tomorrow-framework-ebook/dp/B01N9S0CZN , It explains Angular 5 in depth and it has a chapter about testing.