Memorizing APIs is... not how I'd approach productivity, but if it works for you, great.
I'm doing a lot of Kotlin right now, where simple, useful extension functions are an autocomplete away. I don't need to memorize how to get a slice of an array; I know it's going to be named something like .slice(), and I can jump right to the documentation from my IDE.
When I run into something not in the standard library, I write a little extension function of my own. And then I remember it the next time I run into that problem, and get to reuse it, just like it were part of the language.
I'm doing a lot of Kotlin right now, where simple, useful extension functions are an autocomplete away. I don't need to memorize how to get a slice of an array; I know it's going to be named something like .slice(), and I can jump right to the documentation from my IDE.
When I run into something not in the standard library, I write a little extension function of my own. And then I remember it the next time I run into that problem, and get to reuse it, just like it were part of the language.