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From: Ben Bacarisse <ben.usenet@bsb.me.uk>
Newsgroups: comp.lang.javascript
Subject: Re: x === x
Date: Tue, 30 May 2017 14:34:29 +0100
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ram@zedat.fu-berlin.de (Stefan Ram) writes:

>   In mathematics, usually, when »...« is a certain term, we have
>
> ... === ...
>
>   for the same term left and right.
>
>   In JavaScript, this does not always hold for expressions, albeit
>   possibly sometimes for different reasons:
>
> Math.random() === Math.random()
> NaN === NaN
> [] === []
> ( {} === {} )
> ( ()=>0 )===( ()=>0 )
>
>   In the first case, we cannot be sure that it will evaluate to
>   »false«, but this is is possibly.
>
>   The last three cases are similar, but it is also remarkable 
>   how one needs to add parentheses: no parens required for the
>   array, outer parens for the objects,

What's wrong with {} === {}?

> and two pairs of parens for the functions.

This one makes sense.  You are much more likely to want === in the body
of the arrow function so you want the grammar to cause (x) => x ===
... to mean (x) => (x === ...) rather than ((x) => x) === ...

-- 
Ben.