Webpack Build Errors: An accessor cannot be declared in an ambient context

[douglasg14b]

Expected Behavior

Project builds with webpack through Vue UI.

Current Behavior

It does not, it throws errors.

Steps to Reproduce

1. Start a webpack/Vue Project
2. Add this library
3. Try to build

(Not sure if this is reproducible that way?)

Enviornment

TypeScript 3.5.3

 error  in [RedactedPath]/ClientApp/node_modules/ste-core/dist/dispatching.d.ts

ERROR in [RedactedPath]/ClientApp/node_modules/ste-core/dist/dispatching.d.ts
19:9 An accessor cannot be declared in an ambient context.
    17 |      * @memberOf DispatcherBase
    18 |      */
  > 19 |     get count(): number;
       |         ^
    20 |     /**
    21 |      * Subscribe to the event dispatcher.
    22 |      * @param fn The event handler that is called when the event is dispatched.

 error  in [RedactedPath]/ClientApp/node_modules/ste-core/dist/dispatching.d.ts

ERROR in [RedactedPath]/ClientApp/node_modules/ste-core/dist/dispatching.d.ts
119:9 An accessor cannot be declared in an ambient context.
    117 |      * @memberOf DispatcherWrapper
    118 |      */
  > 119 |     get count(): number;
        |         ^
    120 |     /**
    121 |      * Subscribe to the event dispatcher.
    122 |      * @param fn The event handler that is called when the event is dispatched.

 error  in [RedactedPath]/ClientApp/node_modules/ste-events/dist/events.d.ts

ERROR in [RedactedPath]/ClientApp/node_modules/ste-events/dist/events.d.ts
74:19 An accessor cannot be declared in an ambient context.
    72 |      * Gets the list with all the event dispatchers.
    73 |      */
  > 74 |     protected get events(): EventList<TSender, TArgs>;
       |                   ^
    75 |     /**
    76 |      * Subscribes to the event with the specified name.
    77 |      * @param name The name of the event.

 error  in [RedactedPath]/ClientApp/node_modules/ste-signals/dist/signals.d.ts

ERROR in [RedactedPath]/ClientApp/node_modules/ste-signals/dist/signals.d.ts
45:19 An accessor cannot be declared in an ambient context.
    43 | export declare abstract class SignalHandlingBase implements ISignalHandling {
    44 |     private _events;
  > 45 |     protected get events(): SignalList;
       |                   ^
    46 |     /**
    47 |      * Subscribes once to the event with the specified name.
    48 |      * @param name The name of the event.

 error  in [RedactedPath]/ClientApp/node_modules/ste-simple-events/dist/simple-events.d.ts

ERROR in [RedactedPath]/ClientApp/node_modules/ste-simple-events/dist/simple-events.d.ts
69:19 An accessor cannot be declared in an ambient context.
    67 | export declare abstract class SimpleEventHandlingBase<TArgs> implements ISimpleEventHandling<TArgs> {
    68 |     private _events;
  > 69 |     protected get events(): SimpleEventList<TArgs>;
       |                   ^
    70 |     /**
    71 |      * Subscribes to the event with the specified name.
    72 |      * @param name The name of the event.

[douglasg14b]

Potentially related: https://stackoverflow.com/questions/59502139/ts1086-an-accessor-cannot-be-declared-in-an-ambient-context

Updating TypeScript to see if that resolves this. If it does, this library should make it clear that TS 3.6+ is a requirement.

[douglasg14b]

Upgrading TypeScript resolved this issue.

[KeesCBakker]

That's a great find. Do we need to change something to the package? Or was upgrading your project enough?

[KeesCBakker]

I'll add a comment about being on 3.6+

[douglasg14b]

I believe this should be corrected, as some may have issues upgrading to TS 3.6 or 3.7 if their dependencies don't support it.

I'm not sure what the issue is, but that SO issue is a good start.

[douglasg14b]

https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-7.html#class-field-mitigations

TS 3.7 introduced breaking changes incompatible with TS 3.5 or below, related to typings files I believe.

[mathiasi]

I've just created a fresh AspNet Core project with Angular and I'm facing the same issue however I'm on TypeScript 3.8 so I'm not certain why it still isn't working for me:

Microsoft.AspNetCore.SpaServices: Error: ERROR in ../node_modules/ste-core/dist/dispatching.d.ts:19:9 - error TS1086: An accessor cannot be declared in an ambient context.

19     get count(): number;
           ~~~~~
../node_modules/ste-core/dist/dispatching.d.ts:119:9 - error TS1086: An accessor cannot be declared in an ambient context.

119     get count(): number;
            ~~~~~
../node_modules/ste-events/dist/events.d.ts:74:19 - error TS1086: An accessor cannot be declared in an ambient context.

74     protected get events(): EventList<TSender, TArgs>;
                     ~~~~~~
../node_modules/ste-signals/dist/signals.d.ts:45:19 - error TS1086: An accessor cannot be declared in an ambient context.

45     protected get events(): SignalList;
                     ~~~~~~
../node_modules/ste-simple-events/dist/simple-events.d.ts:69:19 - error TS1086: An accessor cannot be declared in an ambient context.

69     protected get events(): SimpleEventList<TArgs>;
                     ~~~~~~

Edit: using "strongly-typed-events": "1.6.11". I can add "skipLibCheck": true to my tsconfig.json but I would like to avoid that :)

[KeesCBakker]

@mathiasi, did you find a solution?

[mathiasi]

@KeesCBakker Adding "skipLibCheck": true to tsconfig.json was my only solution but it seems more like a workaround :)

[KeesCBakker]

I read others converted

get count(): number;

to

readonly count: number

Might be an option for us as well, but I don't know if it messes the existing usages.

[KeesCBakker]

I'm closing the issue. The issue can be resolved by upgrading TypeScript. Thanks for participating guys.