REPL with ES modules

[ckoncz-hwx]

Search Terms

Is there a way to use ts-node REPL with ES modules?

Expected Behavior

const u = await import('./Util')
should work in the REPL when package type is "module" and Typescript is transpiling to ES modules.

Actual Behavior

$ npx ts-node-esm
> 2+2
/Users/ckoncz/work/git/csaba/ts-node-esm-examples/<repl>.ts:3
export {};
^^^^^^

Uncaught SyntaxError: Unexpected token 'export'
> 2+2
4
> const u = await import('./Util')
Uncaught:
TypeError [ERR_VM_DYNAMIC_IMPORT_CALLBACK_MISSING]: A dynamic import callback was not specified.
    at Object.execCommand (/Users/ckoncz/work/git/csaba/ts-node-esm-examples/node_modules/ts-node/src/repl.ts:633:32)
    at runInContext (/Users/ckoncz/work/git/csaba/ts-node-esm-examples/node_modules/ts-node/src/repl.ts:673:19)
    at Script.runInThisContext (node:vm:129:12)
    at /Users/ckoncz/work/git/csaba/ts-node-esm-examples/<repl>.ts:5:2
    at /Users/ckoncz/work/git/csaba/ts-node-esm-examples/<repl>.ts:1:18
    at importModuleDynamicallyCallback (node:internal/process/esm_loader:39:9)
    at new NodeError (node:internal/errors:387:5)
    at __node_internal_captureLargerStackTrace (node:internal/errors:478:5) {
  code: 'ERR_VM_DYNAMIC_IMPORT_CALLBACK_MISSING'
}
>

Tried it without await:

> import('./Util').then(u=>global.u=u)
Promise {
  <pending>,
  [Symbol(async_id_symbol)]: 84,
  [Symbol(trigger_async_id_symbol)]: 83
}
> Uncaught:
TypeError [ERR_VM_DYNAMIC_IMPORT_CALLBACK_MISSING]: A dynamic import callback was not specified.
    at Object.execCommand (/Users/ckoncz/work/git/csaba/ts-node-esm-examples/node_modules/ts-node/src/repl.ts:639:28)
    at runInContext (/Users/ckoncz/work/git/csaba/ts-node-esm-examples/node_modules/ts-node/src/repl.ts:673:19)
    at Script.runInThisContext (node:vm:129:12)
    at /Users/ckoncz/work/git/csaba/ts-node-esm-examples/<repl>.ts:1:11
    at importModuleDynamicallyCallback (node:internal/process/esm_loader:39:9)
    at new NodeError (node:internal/errors:387:5)
    at __node_internal_captureLargerStackTrace (node:internal/errors:478:5) {
  code: 'ERR_VM_DYNAMIC_IMPORT_CALLBACK_MISSING'
}

Adding '.js' extension does not help:

> import('./Util.js').then(u=>global.u=u)
Promise {
  <pending>,
  [Symbol(async_id_symbol)]: 143,
  [Symbol(trigger_async_id_symbol)]: 142
}
> Uncaught:
TypeError [ERR_VM_DYNAMIC_IMPORT_CALLBACK_MISSING]: A dynamic import callback was not specified.
    at Object.execCommand (/Users/ckoncz/work/git/csaba/ts-node-esm-examples/node_modules/ts-node/src/repl.ts:639:28)
    at runInContext (/Users/ckoncz/work/git/csaba/ts-node-esm-examples/node_modules/ts-node/src/repl.ts:673:19)
    at Script.runInThisContext (node:vm:129:12)
    at /Users/ckoncz/work/git/csaba/ts-node-esm-examples/<repl>.ts:1:11
    at importModuleDynamicallyCallback (node:internal/process/esm_loader:39:9)
    at new NodeError (node:internal/errors:387:5)
    at __node_internal_captureLargerStackTrace (node:internal/errors:478:5) {
  code: 'ERR_VM_DYNAMIC_IMPORT_CALLBACK_MISSING'
}

Steps to reproduce the problem

• Clone felipeplets/esm-examples@61e11ac
• npm install
• Start REPL with npx ts-node-esm
  ( the first line always throws an error. Then the next one might work:

$ npx ts-node-esm
> 2+2
/Users/ckoncz/work/git/csaba/ts-node-esm-examples/dist/<repl>.ts:3
export {};
^^^^^^

Uncaught SyntaxError: Unexpected token 'export'
> 2+2
4

• try to import Util.ts in the REPL.

Minimal reproduction

Specifications

• ts-node version: 10.9.1
• node version: v16.18.1
• TypeScript version: 4.9.3
• tsconfig.json, if you're using one:

{
    "compilerOptions": {
        "lib": ["ES2022", "DOM"],
        "module": "ES2022",
        "moduleResolution": "Node",
        "target": "ES2022",
        "esModuleInterop": true,
        "outDir": "dist/"
    },
    "ts-node": {
        "esm": true,
        "experimentalSpecifierResolution": "node"
    }
}

• package.json:
  https://github.com/felipeplets/esm-examples/blob/61e11ac535a45a6c1f0f2bf5499e40d622c8c8cd/package.json

• Operating system and version: macOS 12.5.1

• If Windows, are you using WSL or WSL2?:

[kasi1999999]

I see last release v10.9.1 many months ago (Jul 14, 2022). Was this fixed? When will it be released?
I tried to use dependency "ts-node": "github:TypeStrong/ts-node#main",, but still getting:

:~/workspace/<company>/sandbox/ts-node-sample$ fnm current
v18.16.0
:~/workspace/<company>/sandbox/ts-node-sample$ npx ts-node --esm
> 
/<company>/sandbox/ts-node-sample/<repl>.ts:2
export {};
^^^^^^

Uncaught SyntaxError: Unexpected token 'export'
> import("./src/hello.js").then(m => console.log(typeof m))
Promise {
  <pending>,
  [Symbol(async_id_symbol)]: 40,
  [Symbol(trigger_async_id_symbol)]: 39
}
> Uncaught:
TypeError [ERR_VM_DYNAMIC_IMPORT_CALLBACK_MISSING]: A dynamic import callback was not specified.
    /node-versions/v16.13.2/installation/lib/node_modules/ts-node/src/repl.ts:639:28)
    /node-versions/v16.13.2/installation/lib/node_modules/ts-node/src/repl.ts:673:19)
    at Script.runInThisContext (node:vm:129:12)
    /<company>/sandbox/ts-node-sample/<repl>.ts:1:11
    at importModuleDynamicallyCallback (node:internal/process/esm_loader:39:9)
    at new NodeError (node:internal/errors:399:5)
    at __node_internal_captureLargerStackTrace (node:internal/errors:490:5) {
  code: 'ERR_VM_DYNAMIC_IMPORT_CALLBACK_MISSING'
}
> import {hello} from "./src/hello.js";
undefined
> hello
/<company>/sandbox/ts-node-sample/<repl>.ts:1
import { hello } from "./src/hello.js";
^^^^^^

Uncaught:
SyntaxError: Cannot use import statement inside the Node.js REPL, alternatively use dynamic import
> 
:~/workspace/<company>/sandbox/ts-node-sample$ cat src/run.ts && echo
import {hello} from "./hello.js";

console.log("Hello from run.ts");
hello();
:~/workspace/<company>/sandbox/ts-node-sample$ npx ts-node --esm src/run.ts 
Hello from run.ts
hello world from hello exported function

package.json:

  "name": "my-package",
  "type": "module",
  "devDependencies": {
    "ts-node": "github:TypeStrong/ts-node#main",
    "tslib": "^2.5.0",
    "typescript": "^5.0.4"
  }
}

tsconfig.json

{
  "compilerOptions": {
    "outDir": "dist",
    "declaration": true,
    "sourceMap": true,
    "target": "esnext",
    "module": "NodeNext",
    "strict": true,
    "allowSyntheticDefaultImports": true,
  },
  "ts-node": {
    "esm": true,
  },
  "include": [
    "src",
    "types",
    "test"
  ]
}

[CherryDT]

Unfortunately, this is not actually fixed! In latest ts-node I get the exact same behavior.