proposal-bind-operator

This-Binding Syntax for ECMAScript

Web Development Libraries & SDKs

Explore on GitHub Read Hacker News discussions

11Distinct people

12Mentions

0Explicit recommenders

1.8KGitHub stars

REPOSITORY AT A GLANCE

What to know before exploring

What it is

This-Binding Syntax for ECMAScript

GitHub

Where it is used

No documented product use has been verified yet.

What people are saying

No recommendation phrase was found in the indexed comments.

No classified warning is attached to this page. Read the discussions before treating silence as approval.

Also in these discussions

No other repository is repeatedly linked in the same discussions.

This week on Hacker News

Nov 7–Nov 14 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/14/2026, 7:02:50 PM UTC.

No direct repository links were found in the indexed HN discussions over the past seven days. Older discussions are available below.

Mentions over time

HN mentions by year12 dated mentions

Observed mentions: 2015-06-12 17:28:02 UTC to 2023-01-20 16:07:31 UTC.

Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.

View mention counts and date ranges

UTC ranges include their start and exclude their end. Select a period to filter the source evidence.
Period	Start (UTC)	End (exclusive, UTC)	Mentions	Submissions	Comments
2015	2015-01-01 00:00:00 UTC	2016-01-01 00:00:00 UTC	3	0	3
2016	2016-01-01 00:00:00 UTC	2017-01-01 00:00:00 UTC	2	1	1
2017	2017-01-01 00:00:00 UTC	2018-01-01 00:00:00 UTC	3	0	3
2018	2018-01-01 00:00:00 UTC	2019-01-01 00:00:00 UTC	0	0	0
2019	2019-01-01 00:00:00 UTC	2020-01-01 00:00:00 UTC	1	0	1
2020	2020-01-01 00:00:00 UTC	2021-01-01 00:00:00 UTC	1	0	1
2021	2021-01-01 00:00:00 UTC	2022-01-01 00:00:00 UTC	0	0	0
2022	2022-01-01 00:00:00 UTC	2023-01-01 00:00:00 UTC	1	0	1
2023	2023-01-01 00:00:00 UTC	2024-01-01 00:00:00 UTC	1	0	1

What Hacker News says

3 sources

spion·Nov 20, 2017

No, there aren't two callable types in JavaScript. Thats precisely the point. Every single function has a `this` argument: function f() { return this + 5; } But there are only two ways to call it: f.call(5) // calls with `this` argument set to 5 and let x = new Number(5) x.f = f; x.f(); // syntax sugar for to x.f.call(x) The confusing part here is that `x.f()` is very different from `x.f`, and is most definitely NOT the same as `(x.f)()`, but more of an `(x.f).call(x)` Other than that and the fact that the argument is always there even if you don't specify it, its exactly the same as Lua, metatables (prototypes) and all. To resolve this confusion once and for all, we desperately need the bind operator [1] to provide a primitive on top of which the rest can be explained. [1]: https://github.com/tc39/proposal-bind-operator

In When I use classes, when I don’t, what I do instead and why

spion·Nov 19, 2017

Because I said left to the dot at "call time". More succintly: > When you call a function, whatever is left of the dot is passed as the `this` argument The analogy is pretty good - you can't pass an argument to a function until you actually call it. In your example, the function hasn't been called yet, so no argument has been passed. foo.doStuff // <-- syntax to access a field member foo.doStuff() // syntax to call a field member with a `this` argument passed left of the dot. Furthermore, on the receiving side, the setTimeout function is seeing: function setTimeout(fn, delay) { // just fn, but not the argument. } Which makes it clear that you can no longer call that function with the proper `this` argument. My point was that `this` is only as confusing as you make it, and there is a simple and straightforward way to teach

Read the rest

it (function argument). If you do that, the dozens of seemingly special cases go down to just a couple. Its unfortunate we don't yet have the bind operator https://github.com/tc39/proposal-bind-operator If we had it, the explanation could be made even clearer. You would be able to call free-standing functions with a `this` argument left of the double colon, i.e. `thisArgument::freeStandingFunction()` - then the dot method call syntax `thisArgument.method()` could be explained as a syntax sugar for `thisArgument::(thisArgument.method)()` - a syntax sugar to at the same time access a function attached as a member field of an object and call it with that object as the `this` argument. The bind operator would make all those other `this` cases seem less special too. Of course you can call various bits of code with whatever `this` argument you want. The event handler code? `someElement::eventHandlerCode(event)`. A constructor? `Object.create(constructor.prototype)::constructor()`. Nothing special here, just a function argument, can have different values in different functions, depending what was passed as `this`. Its bizarre that this operator got stuck in stage 0 and is being subsumed by the pipeline operator (a terrible match for JavaScript). Looks like TC39 isn't interested in untangling the mess.

In When I use classes, when I don’t, what I do instead and why

supergreg·Nov 19, 2017

Looked around and there's a proposal for an easier way to bind `this` and some discussion about extending that to class methods: https://github.com/tc39/proposal-bind-operator/issues/39 Using arrow functions at the class level would also solve this without adding new syntax. Edit, this is a thing already: https://babeljs.io/docs/plugins/transform-class-properties/

In When I use classes, when I don’t, what I do instead and why