Best place to require modules which are only used in closures

If, as part of a NodeJS file, there are different closures:

const Library2 = require('Library2'); // should it be here?

doSomething().then(()=>{
    const Library1 = require('Library1'); // or here?
    return Library1.doSomething();
}).then(()=>{
    return Library2.doSomething();
}).then(...) // etc.

Would it be better to require Library1 and Library2 in the scopes in which they are used? Or at the top of the file like most do?

Does it make a difference to how much memory is consumed either way?

via d-_-b