static methods omitted from 'allowJs' 'declaration' .d.ts

[cspotcode]

TypeScript Version: Version 3.8.0-dev.20200117

Search Terms:

static method omitted
static method missing
allowJs function missing

Code

This is related to mochajs/mocha/issues/4154, where I'm experimenting with generating .d.ts from Mocha's JS source.

Input is JavaScript, with "allowJs" and "declaration" turned on.

module.exports = MyClass;

function MyClass() {}
MyClass.staticMethod = function() {}
MyClass.prototype.method = function() {}
MyClass.staticProperty = 123;

/**
 * Callback to be invoked when test execution is complete.
 *
 * @callback DoneCB
 * @param {number} failures - Number of failures that occurred.
 */

Expected behavior:

With "allowJs" and "declaration" enabled, emits .d.ts that includes staticMethod. I'm not sure whether it should be included in the class body or with the other exports.

export = MyClass;
declare function MyClass(): void;
declare class MyClass {
 method(): void;
 static staticMethod(): void; // <-- maybe it should be declared here?
}
declare namespace MyClass {
 export { staticMethod, staticProperty, DoneCB };
}
declare var staticMethod: () => void; // <-- maybe it should be declared here?
declare var staticProperty: number;
/**
 * Callback to be invoked when test execution is complete.
 */
type DoneCB = (failures: number) => any;

Actual behavior:

staticMethod is missing. (though it is included in the export {...} statement.)

export = MyClass;
declare function MyClass(): void;
declare class MyClass {
 method(): void;
}
declare namespace MyClass {
 export { staticMethod, staticProperty, DoneCB };
}
declare var staticProperty: number;
/**
 * Callback to be invoked when test execution is complete.
 */
type DoneCB = (failures: number) => any;

Playground Link:

I created a repl.it reproduction that calls the compiler, then prints the emitted d.ts.
https://repl.it/@AndrewBradley/missing-static-method

Related Issues:

[weswigham]

Thanks for the detailed bug report! Looks like we were failing to handle things we'd only marked with SymbolFlags.Method (vs SymbolFlags.Property or SymbolFlags.Function) in the binder during declaration generation. I have a PR up with a fix.