Eyas's Blog

Occasional musings on software development, tech, the Middle East, and anything else.

Software Archives | Page 5 of 6

About those Side-effects in Observables, an Angular Use Case

When testing a codebase in Angular Ivy, I ran into a bunch of test failures I wasn't seeing before. ExpressionChangedAfterItHasBeenCheckedError s were being thrown around. In debugging these failures, I found that many of them are the results of side-effects in Observables and Observable pipe operations. I happened to describe these earlier in my piece on Observables, Side-effects, and…

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Observables, Side-effects, and Subscriptions

My previous articles on using AsyncPipe and data refresh patterns in Angular hint at some common anti-patterns dealing with Observables. If there’s any common thread in my advice, it is: delay unpacking an Observable into its scalar types when performing logic you can rewrite as side-effect-free, leaving code with side-effects for subscription callbacks and other downstream logic. My two…

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Data and Page Content Refresh patterns in Angular

Part of why I recommend using RxJS Observable s all the way through in Angular TypeScript code, and only unpacking them at the closest point to where the UI is declared (often using the | async pipe) , is because it makes other transformations on an Observable available and convenient. Two such examples include retry and refresh logic. Two common reasons to reload/refresh data being…

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Use AsyncPipe When Possible

I typically review a fair amount of Angular code at work. One thing I typically encourage is using plain Observable s in an Angular Component, and using AsyncPipe ( foo | async ) from the template html to handle subscription, rather than directly subscribing to an observable in a component TS file. Subscribing in Components Unless you know a subscription you're starting in a component is very…

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The Subscription Model is the Future of Software—and for good reason

Microsoft recently announced the launch of Office for iPad . Many people took note about the pricing model behind Office for iPad: the apps are free to download, and the user can open and view documents, spreadsheets, and presentations for free, but must pay for an Office 365 subscription to edit these files. Many have taken notice. At Microsoft, the move to a subscription-based model has been…

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