Seth Ladd's Blog

Three new language features just landed in the latest dev channel build of the Dart ! Collectively known as null-aware operators , these new features will help you reduce the code required to work with potentially null objects. I'm excited for these new abilities, because typing less is always a good thing. Read on to learn more, and be sure to try these new features on Dart Pad . ?? Use ?? when you want to evaluate and return an expression IFF another expression resolves to null. exp ?? otherExp is similar to ((x) => x == null ? otherExp : x)(exp) ??= Use ??= when you want to assign a value to an object IFF that object is null. Otherwise, return the object. obj ??= value is similar to ((x) => x == null ? obj = value : x)(obj) ?. Use ?. when you want to call a method/getter on an object IFF that object is not null (otherwise, return null). obj?.method() is similar to ((x) => x == null ? null : x.method())(obj) Yo...

Dart 's dartfmt tool is a really neat utility to automatically format your code. Use the dartfmt tool in your workflow to ensure your code complies with the Dart style guide . Of course, you don't want to manually run dartfmt. Instead, you want to automate it. Use git's pre-commit hook to ensure your code is formatted, before it is committed. Add the following code to your . git/hooks/pre-commit script for your local repo, and make sure the script is executable. #!/bin/bash DARTFMT_OUTPUT=`dartfmt -w . | grep Formatted` if [ -n "$DARTFMT_OUTPUT" ]; then   echo $DARTFMT_OUTPUT   echo "Re-attempt commit."   exit 1 else   echo "All Dart files formatted correctly. Yay!"   exit 0 fi If your code needs formatting, it will be formatted and written to disk. The commit will fail, so you have a chance to inspect the changes. You can enforce formatting with your Continuous Integration system. Try these instructions ...

In which I port a snazzy little JavaScript audio web app to Dart , discover a bug, and high-five type annotations. Here's what I learned. [As it says in the header of this blog, I'm a seasoned Dart developer. However, I certainly don't write Dart every day (I wish!). Don't interpret this post as "Hi, I'm new to Dart". Instead, interpret this post as "I'm applying what I've been documenting."] This post analyzes two versions of the same app, both the original (JavaScript) version and the Dart version. The original version is a proxy for any small JavaScript app, there's nothing particularly special about the original version, which is why it made for a good example. This post discusses the differences between the two implementations: file organization, dependencies and modules, shims, classes, type annotations, event handling, calling multiple methods, asynchronous programming, animation, and interop with JavaScript libraries. F...