Microsoft/TypeScript

Typescript can't infer types when using Proxy

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#20.846 geöffnet am 21.12.2017

 (12 Kommentare) (102 Reaktionen) (0 zugewiesene Personen)TypeScript (13.395 Forks)batch import
BugDomain: lib.d.tsHelp Wanted

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Beschreibung

Code

let obj = {
    prop1: function () { },
    prop2: 'hello',
}

let prox = new Proxy(obj, {
    get: function (target, name) {
        return 5;
    }
});

prox.prop1.

Expected behavior: I would expect that when I type prox.prop1., I would get typescript suggestions for Number.prototype, but instead, I get suggestions for Function.prototype. prox.prop1 will (according to typescript) still be callable as a function, but in runtime, it will clearly be a number and will throw an exception.

Statically evaluate the proxy traps and determine the type of thing being returned to offer proper typescript intellisense.

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