Syntax to pick named exports from a module

Gray Zhang otakustay at
Tue Feb 21 13:13:30 UTC 2017

In many cases we need *some* named exports from a module, but currently
there is no syntax to support things like:

import {flatMap, uniq} as _ form 'lodash';

Currently supported syntax could be:

import * as tmp from 'lodash';
let _ = {flatMap: tmp.flatMap, uniq: tmp.uniq};

There are reasons for me to downvote this syntax:

   1. It causes extra lines of code without improving readability
   2. There is no object property pick syntax so I’m required to write
   redundant code
   3. The let statement is not forced to be static so it is not that easy
   for tree shaking, once a developer use dynamic statements in the let
   line it breaks tree shaking

or we may code like this:

import {flatMap, uniq} from 'lodash';
let _ = {flatMap, uniq};

Still it comes with some shortcomings:

   1. It declares too many variables, variables which only used once is not
   a good smell
   2. It cost more efforts to adding or removing selected exports, it could
   fail if I just add a named export in import statement but forget to add
   it in the let line

In this case, I think a import {x, y} as z from 'some' syntax can help, and
it doesn’t seem to conflict with any existing sytnax

Gray Zhang
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