"Ignoring this import because X was marked as having no side effects" on type imports

[fregante]

https://github.com/g-plane/typed-query-selector is a type-only package, it's normal for it to be ignored (related: #1525), but it should not cause a warning.

Repro

npm i -D typed-query-selector

// main.ts
import 'typed-query-selector'
document.querySelector('div#app')

esbuild main.ts --bundle

Expected output

No error

document.querySelector('div#app')

Current output

 > file.ts:1:7: warning: Ignoring this import because "node_modules/typed-query-selector/shim.d.ts" was marked as having no side effects
     1 │ import 'typed-query-selector';
       ╵        ~~~~~~~~~~~~~~~~~~~~~~
   node_modules/typed-query-selector/package.json:13:2: note: "sideEffects" is false in the enclosing "package.json" file
    13 │   "sideEffects": false,
       ╵   ~~~~~~~~~~~~~

[hyrious]

I believe this warning is for preventing people from incorrectly marking a package as no side-effect when it actually has. Normally the import "xxx" statement is used for side effects, like importing from core-js. Esbuild can not ignore this statement like other import types because when you write import "xxx", you expect something happen globally (but this thing happens in types world, so esbuild don't know).

One possible solution is putting this package in the types field in tsconfig.json.

[fregante]

Thanks @evanw!