import from tslib support in deno standard library

[southpolesteve]

I have a few modules that look like they should work with deno, except that they import from tslib. It looks like this was addressed in a PR, but never merged #227. Would the core team be open to reconsidering a similar PR to what was closed?

[aadamsx]

I’m going to be using Azure CosmosDB on my next project and this change is needed by the CosmosDB Dev team to get the relevant lib to incorporate Deno.

[kitsonk]

@southpolesteve that PR didn't do what you wanted that PR to do. It dealt with how internal Deno code would have worked and it wouldn't have been available for runtime code persay.

Though I can see the value in consuming already transpiled TypeScript files that import from tslib. A very logical feature request that just hasn't come up before. Do you have a simple example file of what your emit looks like for one of these files? We can certainly build tslib into the Deno binary and have them available for importing.

[kitsonk]

(as a temporary work around, I believe you could use --unstable and import maps to take the "tslib" import and remap it to somewhere else where tslib existed).

[southpolesteve]

Makes sense. Here is a simple example that would import tslib if importHelpers was turned on:

Source:

const foo = {}
const { bar, ...bax} = foo

Emitted code:

"use strict";
import { __rest } from 'tslib'
const foo = {};
const { bar } = foo, bax = __rest(foo, ["bar"]);

[bartlomieju]

@kitsonk is this issue something that you still want to support?

[kitsonk]

It is something that is fairly trivial to support with import maps, for those using already emitted TypeScript. Feels like something we should add to the manual of how to use an import map to do this.