How to import enums from npm:typescript package?

The following code crashes because the enum is undefined at runtime.

import * as ts from "npm:typescript";
console.log(ts.ScriptTarget.ESNext);

import * as ts from "npm:typescript";
console.log(ts.ScriptTarget.ESNext);

error: Uncaught (in promise) TypeError: Cannot read properties of undefined (reading 'ESNext')
  target: ts.ScriptTarget.ESNext,

error: Uncaught (in promise) TypeError: Cannot read properties of undefined (reading 'ESNext')
  target: ts.ScriptTarget.ESNext,

I think this issue is related, but I can't figure out how to actually solve this. https://github.com/denoland/deno/issues/7605 I tried running it in Bun and it worked as expected and I can't find any compiler options in deno that seem related. How should I fix this?

GitHub

const enum error clarification · Issue #7605 · denoland/deno

This error appears after I switched to Deno 1.4.1 and fixed all the import type errors. Skillz@Home Discordeno % deno run --allow-net --allow-read --unstable debug.ts error: Uncaught ReferenceError...

4 Replies

marvinh.•7mo ago

-  import * as ts from "npm:typescript";
+ import ts from "npm:typescript";

-  import * as ts from "npm:typescript";
+ import ts from "npm:typescript";

JacobZwangOP•7mo ago

oh huh, why does this work? and why does this also not work?

import { ScriptTarget } from "npm:typescript";
console.log(ScriptTarget.ESNext);

import { ScriptTarget } from "npm:typescript";
console.log(ScriptTarget.ESNext);

marvinh.•7mo ago

Because they don't export named variables, they export a namespace in their package:

namespace ts {
  // ...
}

export = ts

namespace ts {
  // ...
}

export = ts

JacobZwangOP•7mo ago

ah, I see. thanks!