🤝 Open source advocate 👽 Maintainer of @stryker_mutator 💼 Manager and trainer @InfoSupportBV 💚 Loves green energy and vegetables
Holland and Belgium
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How can a lonely JS program know whether or not it is executed in an ES module or a plain script? 🤷♂️ stackoverflow.com/questions/…
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Sneak preview: the next version of StrykerJS will detect and break infinite loops (or at least tries to) github.com/stryker-mutator/s…
I've been thinking of ways to improve handle infinite loops in mutation testing scenarios. Feedback welcome github.com/stryker-mutator/s…
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Nico Jansen retweeted
Since the Paris Agreement was signed 5 yrs ago, G20 states have subsidised fossil fuels by more than 3.3 trillion dollars.
Only *2%* of their financial support after the pandemic has gone to clean energy transitions.
#MindTheGap between words and action.
theguardian.com/environment/…
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These are my favorite test classes in the entire StrykerJS code base. They remind me of a simpler time playing GoldenEye 007 on N64 with friends and my brother 😍
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Nico Jansen retweeted
And if thy lint rule offends thy code, disable it, and cast it from thy config file: for it is profitable that one line of code be wonky, and not that thy whole code base should be cast into disorder - Matthew 5:29
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I long for a time that I don't have to say "Native promises" anymore. The "native" part should be implied.
Are there still reasons to roll your own promises in 2021 🤔?
Nico Jansen retweeted
Announcing: I'm writing an @OReillyMedia book on introductory @TypeScript! 🎉
✨ It's targeted to devs who can write JavaScript but don't necessarily have compiled / type language experience. ✨
We're tentatively calling in "Learning TypeScript" or "Beginning TypeScript".
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Nico Jansen retweeted
StrykerJS 5.2 just released 🎉
With more goodness 🎁
❓ Optional chaining mutator
🥒Support for cucumber-js as a test runner. See stryker-mutator.io/docs/stry…
Start mutation testing today! stryker-mutator.io
@cucumberbdd
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I could have lived an entire life without having `undefined` in #javascript 🤷♂️
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I'm missing the "error TS1234" option in all of these questions😎 jsisweird.com/
F*ck my life 🙄 github.com/stryker-mutator/s…
Any chance I'm making some @cucumberbdd users happy?
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I've spent the past weeks thinking of the best possible solution and I'm implementing it. You can follow the progress here: github.com/stryker-mutator/s…
Just another day (or month) in the life of a Mutation testing framework maintainer.
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Basically, when StrykerJS places the optional chaining mutant it has _already placed_ the "deeper" arithmetic operator mutant and thus it duplicated with the `cloneNode(deep: true)`.
This is a bug in our placing algorithm, not a specific mutator. 🙄
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Where does this bug come from?
StrykerJS uses @babeljs to place mutants, which uses a mutable Abstract Syntax Tree (AST). The way StrykerJS places mutants in the code is by using a combination of the visitor pattern, cloneNode(deep: true), and "NodePath.prototype.replaceWith".
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Side note: you might think this isn't worth fixing, but we have the goal of supporting all JS projects, also the ones with 1000+ LoC / file and deep AST's. I find the "prettier" code base to be an excellent example for files with such complexity
github.com/prettier/prettier
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