microsoft / microsoft/TypeScript

Un used variable is emmitted while transpiling enums.

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Description

TypeScript code


module Workspace {
  export enum State {
    IN_PROGRESS,
    BUFFER_RENDERED,
    SKIPPED,
    TIME_OUT
  }
}

Compled JavaScript Code.

 
var Workspace;
(function (Workspace) {
    (function (State) {
        State[State["IN_PROGRESS"] = 0] = "IN_PROGRESS";
        State[State["BUFFER_RENDERED"] = 1] = "BUFFER_RENDERED";
        State[State["SKIPPED"] = 2] = "SKIPPED";
        State[State["TIME_OUT"] = 3] = "TIME_OUT";
    })(Workspace.State || (Workspace.State = {}));
    var State = Workspace.State; // this code is use no where.
})(Workspace || (Workspace = {}));

I am using TypeScript version 1.5.3

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Research direction

Reproduce the enum example with TypeScript 1.5.3 and compare the emitted JavaScript with the report. Trace the enum transpilation path that emits the unused State variable; done means the equivalent unused variable is no longer emitted without changing the enum behavior.

Written by the indexing model from the issue text.

Assessment

Tech stack
typescript
Domain
compilers
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
30/100

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