Even if you knew every function in every lib in your head, typing with autocompletion from some good IDE like IntelliJ will make you write code much much faster. And I do not talk about just function name completion (but include them too of course).

Typing just the first or few random letters of veryDescriptiveLongMethodName and completing it with space/tab will always be faster. Using stuff like templates, smart completion, emmet, refactoring tool, constructor/method generators will always be faster, if you know your tools well.