You Don't Know JS Yet
A book series that goes deliberately deep on the mechanics of JavaScript, including scope, closures, coercion, the object system and asynchrony. Read it when you are tired of language behaviour surprising you.
Book
Web Development
Kyle Simpson
2 to 4 months
Advanced
Free
What it is
A multi book series, free in its entirety on GitHub, examining JavaScript in genuine depth rather than teaching it. Scope and closures, objects and classes, types and grammar, asynchrony and performance each get a book.
Who it is for
Not beginners. This is for developers who are already productive and keep encountering behaviour they cannot explain: why a comparison did that, why this is not what they expected, why a value coerced the way it did. The series takes the position that these are learnable rules rather than quirks to avoid, and then teaches the rules.
How to use it
Read one book, not the set. Scope and Closures is the one that changes the most for the most people, and it stands alone.
Best for: intermediate developers who want to stop guessing about their main language.
Ready to start?
Opens on Kyle Simpson in a new tab.
Stuck on something specific?
Writing only gets you so far. If you want an answer to your situation rather than the general case, book a session and we will work through it together. Every session is free; a few slots open each week.
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