Are you familiar with [Symbol.iterator]()? It's doing the same thing. {[someValue]: ...} is a pattern used when initializing computed keys on objects [1]. Some

Are you familiar with [Symbol.iterator]()? It's doing the same thing. {[someValue]: ...} is a pattern used when initializing computed keys on objects [1]. Some people might not encounter it often, though. Symbol.* is sometimes used to implement language-level methods, like Symbol.dispose here or Symbol.iterator in my example below [2]. JS knows what those are for, and has well-defined and documented ways of using them. I think — and I'm willing to be wrong — it's a pretty useful convention once it clicks, and while it might be confusing at first, I've come to like it. In the iterator example, you can see how you can create a dynamic data structure from a POJO (generating 52 cards from only the suits and ranks of a deck, and being able to treat it like an array). It's a useful way to encapsulate data and logic about a collection of data. When combined with generators, this pattern is extremely powerful. But again, this is why some people might not encounter it often. 1. https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Object_initializer#computed_property_names https://developer.mozilla.org/en-US/docs/Web/JavaScript/Refe... 2. https://codesandbox.io/s/keen-swartz-7yrls3?file=/src/index.ts https://codesandbox.io/s/keen-swartz-7yrls3?file=/src/index....