TypeScript compilation: declare const is not de-referenced properly

[iamakulov]

Hey,

I stumbled upon a ESBuild bug with the following piece of code (simplified from a real project):

export namespace Assets {
    export declare const service: string

    export function on(channel: string) {
        return someCall(service, channel) // ← A
    }
}

// Later: assign the actual `service` implementation
(Assets as any).service = getTheServiceFromSomewhere()

ESBuild seems to leave the service reference at line A as-is. This results in Uncaught ReferenceError: service is not defined.

TypeScript output (playground):

export var Assets;
(function (Assets) {
    function on(channel) {
        // ↓ Note how `service` is de-referenced to `Assets.service`
        return someCall(Assets.service, channel);
    }
    Assets.on = on;
})(Assets || (Assets = {}));
// Later: assign the actual `service` implementation
Assets.service = getTheServiceFromSomewhere();

ESBuild output:

// ...
var Assets;
(function(Assets2) {
    function on(channel) {
    // ↓ Note how `service` is kept as-is
    return someCall(service, channel);
    }
    Assets2.on = on;
})(Assets || (Assets = {}));
Assets.service = getTheServiceFromSomewhere();

Compiled with:

esbuild --bundle test.ts --outfile=out.js

[evanw]

Interesting. Thanks for reporting this. This will be good to fix.

[evanw]

This should be fixed in version 0.5.23.