Reconsidering the name "lettable"?

Lettable operators look awesome, and I understand where the name comes from, but it’s a bit confusing, and will be especially confusing to newcomers once the let operator is not in common use.

Have you considered as an alternative “pipeable” operators? Also maybe not great, but it has the advantage of making it clear that these are the operators you use with pipe().

[cartant]

Before it becomes regrettable?

[Jerry-Hong]

I think composable operators is more reasonable. it is from functional programming concept, we can use it with ramda.js

import R from 'ramda';
import { filter, map } from 'rxjs/operators'
import { from } from 'rxjs/observable/from'

const obs1 = from([1,2,3]);
const obs2 = from([4,5,6]);

const getOddAndToString = R.compose(map(x => x + ''), filter(x => x % 2 === 1));
// same as pipe: 
// const getOddAndToString = R.pipe(filter(x => x % 2 === 1), map(x => x + ''))

getOddAndToString(obs1)
.subscribe(...)

getOddAndToString(obs2)
.subscribe(...)