understand bind and prototypage

[stray moon]

hello for example a discordjs event is like this:
bot.on(event_string, lamda function)
so the prototypage of bot.on is a string and interface? bot.on(event_name, interface_x)?

[arctic star]

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[cinder plume]

what?

none of that seems really connected

can you clarify what you're trying to understand here

[stray moon]

the bot.on function expects a parmameter, a string (eventname) and a function/lambda, right?

[cinder plume]

yeah

[stray moon]

so the protoypage of this function as an argument expects a string and a functional interface, right?

[cinder plume]

no

"prototypage" isn't a term used

prototypes are a completely different thing from this

[stray moon]

I mean where it's created (in the djs lib)

[cinder plume]

what you're describing is the parameter list of the function, which is part of the signature

also no functional interfaces here, that's a java feature
js just has functions, straight up

the form () => {} is an arrow function in js

[stray moon]

yes like lambda in other languages i think

so the 2nd args waited is arrow function?

[cinder plume]

works like a lambda, sometimes but usually not called a lambda, but definitely not a functional interface

[cinder plume]

any function with the right signature. "arrow function" describes the syntax, not what it creates (although there are some differences between arrow functions and functions made in other ways, but that's not important here)

keep in mind that the types aren't enforced by js

so you could pass any value, or a function with the wrong signature, and js would let you, you'd just get runtime errors

[stray moon]

okay and on the event. The djs lib add argument (event) probably in the function first parameter right?

[cinder plume]

what?

your question isn't coherent there

[stray moon]

client.on("messagecreateblabl", (event) => {})

at the message create this function got called and djs give argument for event (with sender etc...) right?

[cinder plume]

yes

[stray moon]

okay so

bot.on(file.split(".js").join(""), event.bind(null, bot))

is a event handler's system

so event.bind(null, bot)) is our function executed on the event. bind is here to pass the client instance (bot) at the module is that?

other argument like (event) or message sometimes are auto passed after bot?

(the module event is like this event(bot, event/message ...)

[cinder plume]

bind is a method of functions that returns a modified function, that basically pre-sets the this value and however many arguments you give

so if you had a function handleMessage(client, message), calling bind(null, bot) on it would preset the this value as null, the client parameter as bot, and then return a function that's waiting to accept the message still

[stray moon]

by just doing event(bot) it would call event at levent time but there couldn't be any other arguments than bot right?

whereas bind allows

[serene spire]

It would call the event function when reaching that .on statement, not when the event is emitted in that case. Which you don’t want

[stray moon]

ah yes, it wouldn't take into account the "callback"

but why is it that with even an arrow function it waits for the event to activate, whereas if you include a function directly it doesn't?

[cinder plume]

if you include a function directly it does

but handler(bot) is not a function, it is a function call

[stray moon]

why it does for a function but no for arrow function?

[cinder plume]

it does for an arrow function too

it's passed as a callback, waiting to be called, if you pass a function, any kind, including an arrow function
the difference is that handler(bot) is a function call, not a function.

handler.bind(null, bot) is also a function call. the bind is executed immediately, it just returns another function that's actually passed and used as a callback

[stray moon]

ah okay

thanks for your brightening

[stray moon]

Is the fact that other args such as event are automatically added after bot a bing-specific property?

[serene spire]

function.bind(thisArg, …args) just returns a function that basically is (…otherArgs) => function(…[…args, …otherArgs]) (ignoring how the this parameter gets set)

[stray moon]

So is a bind proprety

And bond return
(Otherargs like event) => function(client passed in bind, otherargs like event )?

[serene spire]

I‘m sorry but I don’t understand your question

[stray moon]

I mean, what is it that makes other argumenhts such as message, (generated by discord api) be added to the suite in our event(bot, "suite") function that is automatically done by bot.on?

[serene spire]

The fact that when the bot receives a messageCreate payload from the gateway websocket it‘ll call <Client>.emit('messageCreate', message)
There’s no magic there, it‘s just literally called with those parameters

[stray moon]

And other args are auto passed after bot in my event(bot)?

[serene spire]

What event(bot)? There is no such function and if you made one named like that you should show it for me to be able to answer that question

[stray moon]

event is just a module/function for my event handler (1 file per event) event() wait client instance and event like message

event(bot, message)

but with bind i just do event.bind(null, bot) and i want understand how its possible that message is auto aded after bot for event

[serene spire]

because event.bind(null, bot)(message) is the same as event(bot, message) (if we ignore the this reference)

There’s nothing getting Auto added. It‘s literally called with those parameters

[stray moon]

so in my bot.on(messagecreate, event.bind(bull, bot)) the bot.on methode is maded to add message in arg at the function in second args of it(bot.on)? right?