member-ordering's variables-before-functions treat function properties as methods

[mgol]

Bug Report

• TSLint version: 5.7.0, whatever the playground uses
• TypeScript version: 2.8.3, whatever the playground uses
• Running TSLint via: (pick one) CLI / Playground

TypeScript code being linted

// A fake debounce implementation.
const debounce = (fn, delay) => setTimeout(fn, delay);

class C {
    value = 42;
    returnValue = () => this.value;
    debouncedReturnValue = debounce(this.returnValue, 1000);
}

with tslint.json configuration:

{
    "rules": {
        "member-ordering": [true,
            "variables-before-functions"
        ]
    }
}

See it in the playground: https://palantir.github.io/tslint-playground/?saved=N4Igxg9gJgpiBcID0SAEBBVAzAhgaxlVgCMIBXAOzEIEsBbABwBsY6YKAXHDmiCgOgA6VPgGcORGKUrVUAXlQAKLBQA0kpjgCeASnkA+VKJgcAKvRjkOytRu06A3MOFhNo0agDCqYMNT-UADccJjJCBQAWACYnCgDUACcTMgSKADUQsPklPTlDDgALGlF+YNCYWPiScioYKAAlZNSM8uzqmRhFQuL+JI4U9MyYdQBGAAYJx2EAX2EQVXA+LBoAcwQQXziAwRAEshZRHfgfP3jtkDY6YhgEgFoIBNgEmgoVo9QAbQ494dOzs52wWeOGIB1u1ywDxgtywMh4Yh2fzOAF0kbMKOiQNMgA

Actual behavior

It errors with:

Declaration of field not allowed after declaration of method. Instead, this should come at the beginning of the class/interface.

Expected behavior

There should be no error.

The problem is TSLint treats class fields defined as functions as methods when they are not methods. This creates problems - for methods, their order doesn't matter. For fields it sometimes does. In my example I have two fields with function values, the second one of them created not directly but by another function. I cannot change the order of those fields as the debounced returnValue function must already be defined when debouncedReturnValue is being defined.

[pcroc]

We have the same issue, where an arrow function assigned to a variable is treated as a method.

This rule should provide the option of whether to treat arrow functions as methods or not, and/or a way to disable this rule for a particular line:

// (This doesn't work)

// tslint:disable-next-line:member-order
public filter = (text: string) => this.defaultFilter(text); 

[mgol]

@pcroc You made a typo in the rule name. Disabling it just for the next line works fine.

[JoshuaKGoldberg]

Duplicate of #3589.