[monocdk] Unable to create custom stacks that extend Stack

When trying to synthesize a custom Stack (which extends Stack), I receive the below error:

“Class constructor Stack cannot be invoked without ‘new’”

Here is the erroneous sample code:

export class FooStack extends Stack {
    constructor(construct: Construct) {
        super(construct);

        new MyCustomConstruct(construct, "test");
    }

}

const app = new App();
const stack = new FooStack(app);
app.synth();

However if using the Stack directly it works just fine as per the below sample code:

const app = new App();
const stack = new Stack(app, "testStack");
new SecureBucket(stack, 'test');
app.synth();

I am using the Construct from monocdk, tried with the Construct from the constructs package however received a different error relating to cannot find children.

Reproduction Steps

export class FooStack extends Stack {
    constructor(construct: Construct) {
        super(construct);

        new MyCustomConstruct(construct, "test");
    }

}

const app = new App();
const stack = new FooStack(app);
app.synth();

What did you expect to happen?

Stack should syntesize.

What actually happened?

Class constructor Stack cannot be invoked without ‘new’

Environment

• CDK CLI Version : 1.71.0 (build 953bc25)
• Framework Version: “constructs”: “3.0.4”, “monocdk”: “1.69.0”
• Node.js Version: v14.14.0
• OS : OS/X Catalina
• Language (Version): Typescript 3.9.5

---

This is 🐛 Bug Report

[ritesh]

@blimmer thanks for sharing this! I ran into the same issue, but mine was due to a missing tsconfig.json. To resolve it, I created a new cdk project in a temporary directory and copied the tsconfig.json over.

[blimmer]

In case someone else finds this issue searching for the Class constructor Stack cannot be invoked without 'new' error message, I ran into this problem with an internal, shared CDK library using tsdx to bundle. By default, it bundles for a web target, which was not exposing true Javascript classes in the output.

To fix it, I needed to use tsdx build --target node. Hopefully this helps someone else!