PerformanceJS

a blog by Boris Cherny

Options in TypeScript

If you wrote in Scala or Haskell before you tried TypeScript, you may have found yourself wondering: Where are the Options at?

For those not familiar, here is an excellent introduction to Scala’s Option type. At a high level, Option is an abstraction over null that gives useful semantics around running functions over possibly-null values. It implements a monad, a functor, and some other structures, but that’s not important for this post.

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Introducing: Lazy Arrays in JavaScript

Today I’m introducing lazy-arr, which brings lazy arrays to JavaScript.

What’s a lazy array and why is it useful?

Flashback to your job interview for your first software engineering job: let’s write a Fibonacci function. We define the base cases of 0 and 1, then recurse to generate the rest:

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