Executing a function from a string using dynamic import | TypeScript Community | Page 1

lapis knoll Mar 11, 2023, 6:43 AM

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Hello, how can I execute whatever is parameter, for example, I have a const in ../constants/support called debug, how can I make execute like support.debug, but instead of debug use a string that I'm passing

const support = await import("../constants/support");
support.Function(parameter);```

lapis knoll Mar 11, 2023, 7:16 AM

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!resolve

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Actually, my bad, my idea was to instead return something else in the function but forgot I won't still be able to call it

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!reopen

odd flax Mar 11, 2023, 11:14 AM

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Do you mean something like

const level = "debug";

const support = await import("../constants/support");

support[level](parameter);

lapis knoll Mar 11, 2023, 12:43 PM

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I'll test out in a couple of minutes

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Actually, my bad, no

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I have a parameter

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For example

const parameter = "debug";

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And I need to run the parameter via support.

left dust Mar 11, 2023, 2:34 PM

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@lapis knoll while what you're trying to do might work, I would not recommend it

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running code from a string is not ideal

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also the fact the code is a strig doesn't give you any type checking, etc.

lapis knoll Mar 11, 2023, 2:35 PM

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Hey, so I made a list string[], if the parameter is not in the array, then error

lapis knoll Mar 11, 2023, 4:52 PM

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Ok well, so if debug is not in a list

const list = ["notdebug", "a"];```
then error, if notdebug is the parameter, run notdebug

lapis knoll Mar 12, 2023, 5:37 AM

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!helper

topaz grove Mar 12, 2023, 5:54 AM

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what

lapis knoll Mar 12, 2023, 5:55 AM

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Something like this https://stackoverflow.com/a/62455421, but I don't know how to implement it in my situation

topaz grove Mar 12, 2023, 5:55 AM

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supportparameter?

lapis knoll Mar 12, 2023, 5:56 AM

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No index signature with a parameter of type 'string' was found on type 'typeof import .....

topaz grove Mar 12, 2023, 5:56 AM

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well obviously parameter is a string

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thus its not safe

lapis knoll Mar 12, 2023, 5:56 AM

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In the const file I'm using EmbedBuilder class and cannot be a string

topaz grove Mar 12, 2023, 5:56 AM

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many ways to fix

lapis knoll Mar 12, 2023, 5:57 AM

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Well do you have any ideas?

topaz grove Mar 12, 2023, 5:57 AM

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one way would be to use as any there 🧠

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other proper way would to use a type guard function

topaz grove Mar 12, 2023, 5:58 AM

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lapis knoll In the const file I'm using `EmbedBuilder` class and cannot be a string

you are reading the error wrong

lapis knoll Mar 12, 2023, 5:58 AM

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Probably I can convert the const to a function, but would that still work the same?

topaz grove Mar 12, 2023, 5:58 AM

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what const

lapis knoll Mar 12, 2023, 5:59 AM

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I mean this works

    const support = await import("../constants/support") as any;
    [support[parameter]()]```
just haven't executed the code to test

topaz grove Mar 12, 2023, 5:59 AM

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no not that as any

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parameter as any

lapis knoll Mar 12, 2023, 5:59 AM

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topaz grove what const

export const notdebug = () => {}```

lapis knoll Mar 12, 2023, 5:59 AM

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topaz grove parameter as any

Well Element implicitly has an 'any' type because expression of type 'any' can't be used to index type 'typeof import ....

topaz grove Mar 12, 2023, 5:59 AM

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its already a function?

lapis knoll Mar 12, 2023, 6:00 AM

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Oh, then my bad

lapis knoll Mar 12, 2023, 6:01 AM

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lapis knoll I mean this works ```ts const support = await import("../constants/support")...

If I make the import as any it only works that way, I'll go ahead and try to execute the code

topaz grove Mar 12, 2023, 6:04 AM

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btw does support file export the same function signatures but different functionalities?

lapis knoll Mar 12, 2023, 6:05 AM

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lapis knoll I mean this works ```ts const support = await import("../constants/support")...

Well that worked perfectly

lapis knoll Mar 12, 2023, 6:05 AM

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topaz grove btw does support file export the same function signatures but different function...

What do you mean?

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Ah well if parameter === "notdebug", then it would run export const notdebug = () => {}

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But still, is it alright to make the import as any?

topaz grove Mar 12, 2023, 6:06 AM

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lapis knoll But still, is it alright to make the import as any?

if you are asking this question you should have written it in javascript

topaz grove Mar 12, 2023, 6:06 AM

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lapis knoll But still, is it alright to make the import as any?

imo, no, and ill never do that

lapis knoll Mar 12, 2023, 6:09 AM

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Well do you have any suggestions on how would I make it not any? I mean (support[parameter] as String) thought going to be fine but no

topaz grove Mar 12, 2023, 6:09 AM

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lapis knoll Well do you have any suggestions on how would I make it not any? I mean `(suppor...

support[parameter as any]

lapis knoll Mar 12, 2023, 6:10 AM

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lapis knoll Well `Element implicitly has an 'any' type because expression of type 'any' can'...

Yea well going back to ^

topaz grove Mar 12, 2023, 6:10 AM

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would help marginally

topaz grove Mar 12, 2023, 6:10 AM

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topaz grove btw does support file export the same function signatures but different function...

that assumes this brw

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btw*

lapis knoll Mar 12, 2023, 6:11 AM

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Currently confused, I guess you mean is my function has an any type? If so, no

topaz grove Mar 12, 2023, 6:28 AM

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lapis knoll Currently confused, I guess you mean is my function has an any type? If so, no

no like,
export const debug = (msg: string) => {}
export const warn = (msg: string) => {}
export const info = (msg: string) => {}

lapis knoll Mar 12, 2023, 6:29 AM

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I got export const debug = (guild: Guild) => {}, so I did support[parameter as any](interaction.guild)

lapis knoll Mar 12, 2023, 6:55 AM

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Would this be my solution?

    const support = await import("../constants/support") as string;
support[parameter as string](interaction.guild)```

if so, I got 2 errors, first one VSC tells me to do `import("...") as unknown as string`, second `Element implicitly has an 'any' type because index expression is not of type 'number'.` on parameter, but I've did `let parameter: string` also

lapis knoll Mar 13, 2023, 6:17 AM

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!helper

static sinew Mar 13, 2023, 6:17 AM

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whats the problem now

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are you asking about your solution?

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or are you looking for a solution to the original problem

lapis knoll Mar 13, 2023, 6:18 AM

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Currently both, but I guess the best solution is my current solution, but it needs fixing

topaz grove Mar 13, 2023, 6:30 AM

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@lapis knoll is this someone elses code base

lapis knoll Mar 13, 2023, 6:31 AM

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What do you mean?

topaz grove Mar 13, 2023, 6:31 AM

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did you write the entire code

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of the project or mo

lapis knoll Mar 13, 2023, 6:32 AM

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Yes I did the entire code, most I did, like 25% my friend

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Why?

topaz grove Mar 13, 2023, 6:32 AM

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how do you usually fix ts errors

lapis knoll Mar 13, 2023, 6:32 AM

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Well such as?

topaz grove Mar 13, 2023, 6:33 AM

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variable 's' is type unknown

lapis knoll Mar 13, 2023, 6:34 AM

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Well in most solutions I would just make sure the string is required, but I've never used dynamic imports

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Oh well in this example making the const string worked, but import is not assignable tho, basically the same thing

topaz grove Mar 13, 2023, 6:35 AM

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this isn't a 100% correct representation but you can think of a module as an object

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so await import("...") would be an object

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if you are doing support[parameter as string], it has the same effect as SomeType[string] and that will be the union of all possible members

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but there are two catches

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(typeof support)[string] is not guaranteed to be valid since string is not limited to keyof support

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so

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lets say you convince TS that it is using as any

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support[parameter as any]

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the value of that will be the union of all valid members

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if one of the members are different from another, it will be tricky for you to call

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or, you can ignore this using // @ts-ignore and come back later

lapis knoll Mar 13, 2023, 6:41 AM

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Well parameter doesn't currently matter, because if you even make the import as any, it would work, but not ideal, so if I would need to make the import as a type which I currently don't know, so I'm here

topaz grove Mar 13, 2023, 6:43 AM

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well, i suggest making a typeguard

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for parameter

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when starting out typescript it can be hard

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and often times somethings are obvious while others need more understanding of the comiler and language itself to fully comprehend

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its good that you are trying to get things right but right now, its a little hard for you to do that

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you might end up in a rabbit hole and never finish your project

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so, try focus on making it work. this won't be your last project anyway, so at least show that it works before realising what you can do better

lapis knoll Mar 13, 2023, 6:47 AM

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Well parameter is string by

let parameter: string = interaction.options.getString("parameter", true); // could return anything, such as "notdebug"```
using let because I've made
```ts
if (parameter.includes("/"))
  parameter = parameter.replace("/", "_");```
But the error is happening on import, because it cannot be a typeof string, so I'm here asking, what should it be?

topaz grove Mar 13, 2023, 6:48 AM

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do you know what the parameter can be

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actually, whats the most likely string it can be

lapis knoll Mar 13, 2023, 6:49 AM

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Well d.js also has options when calling an interaction with slash commands in my example, so getString is
public getString(name: string, required: true): string;

topaz grove Mar 13, 2023, 6:50 AM

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no like

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when the code actually runs support[parameter]

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what is parameter

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most likely going to be

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im trying to help you monkey patch this

lapis knoll Mar 13, 2023, 6:52 AM

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It could be anything that users can type, if the string is notdebug in the parameter, then I would simply need support.notdebug()

topaz grove Mar 13, 2023, 6:52 AM

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what if user does

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asdf

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its gonna call

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support.asdf()

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and your bot will crash because undefined is not a function

lapis knoll Mar 13, 2023, 6:53 AM

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Well if asdf is in a string[], then yes

topaz grove Mar 13, 2023, 6:53 AM

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ok, what is that string[]

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show

lapis knoll Mar 13, 2023, 6:54 AM

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const list = ["notdebug", "somethingrandom"];
if (!list.includes(parameter))
  return throw new Error("literally an example");```

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I'm not actually using throw, just returning an interaction.reply

topaz grove Mar 13, 2023, 6:54 AM

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const list = ["notdebug", "somethingrandom"] as const;
type ValidMethod = (typeof list)[number];
function isValidMethod(method: string): method is ValidMethod {
  return list.includes(method);
}

lapis knoll Mar 13, 2023, 6:58 AM

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Right, but Argument of type 'T' is not assignable to parameter of type "'notdebug ... and T cannot be used as a type in a value

topaz grove Mar 13, 2023, 6:58 AM

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oh crap

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there

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https://www.typescriptlang.org/docs/handbook/2/narrowing.html#using-type-predicates

Documentation - Narrowing

Understand how TypeScript uses JavaScript knowledge to reduce the amount of type syntax in your projects.

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read this

lapis knoll Mar 13, 2023, 7:03 AM

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Well I did

function isValidFunction(method: string): method is ValidMethod {
  return list.includes(method);
}``` removing the <>, but now method in the .includes is somehow not assingable to `"notdebug" | "somethingrandom"'`

topaz grove Mar 13, 2023, 7:04 AM

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where

lapis knoll Mar 13, 2023, 7:04 AM

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lapis knoll Well I did ```ts function isValidFunction(method: string): method is ValidMethod...

mb edited the message

topaz grove Mar 13, 2023, 7:05 AM

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oh um, wow typescript got better

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change the code to this

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type ValidMethod = "notdebug" | "somethingrandom";
const list = ["notdebug", "somethingrandom"] satisfies ValidMethod[];
function isValidMethod(method: string): method is ValidMethod {
  return list.includes(method);
}

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basically, they improved the type system of builtins i think

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correct me if im wrong, others

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anyway, this way list is string[] and the code should work

lapis knoll Mar 13, 2023, 7:08 AM

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That didn't work, but I'm going to change the list too, when going into reviewing, also VSC formatting making me do this ]satisfies

topaz grove Mar 13, 2023, 7:08 AM

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whats your ts version

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wdym by didn't work

lapis knoll Mar 13, 2023, 7:09 AM

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Same error, TS 4.9.5

topaz grove Mar 13, 2023, 7:10 AM

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oh myb

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const list: string[] = ["notdebug", "somethingrandom"] satisfies ValidMethod[];

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isValidFunction will help you narrow down parameter to either of those strings

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and typescript won't complain about doing support[parameter]

lapis knoll Mar 13, 2023, 7:12 AM

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Unfortunatly it does complain about ^

Element implicitly has an 'any' type because expression of type 'string' can't be used to index type 'typeof ...
No index signature with a parameter of type 'string' was found on type 'typeof ...```

topaz grove Mar 13, 2023, 7:18 AM

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@lapis knoll whats the code

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oh wait

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what

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where

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whats the code

lapis knoll Mar 13, 2023, 7:18 AM

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on support[parameter]

topaz grove Mar 13, 2023, 7:18 AM

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whats support

lapis knoll Mar 13, 2023, 7:20 AM

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const list: string[] = ["notdebug", "somethingrandom"]satisfies ValidMethod[];
type ValidMethod = "notdebug" | "somethingrandom";
function isValidMethod(method: string): method is ValidMethod {
  return list.includes(method);
}

if (!isValidMethod(parameter))
  return interaction.reply(...);

if (parameter.includes("/"))
  parameter = parameter.replace("/", "_");

const support = await import("../constants/support");
....... support[parameter]() ......```

topaz grove Mar 13, 2023, 7:20 AM

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no no you do it like

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if (isValidMethod(parameter)) {
supportparameter
}

lapis knoll Mar 13, 2023, 7:22 AM

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That does nothing new, basically just remove the ! and makes the code switch places, tried it, same error on support[parameter]

topaz grove Mar 13, 2023, 7:23 AM

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its going to help you catch bugs later anyway

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how are you exporting the functions btw

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in the support file

lapis knoll Mar 13, 2023, 7:40 AM

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lapis knoll Ah well if parameter === "notdebug", then it would run `export const notdebug = ...

my bad, ^

topaz grove Mar 13, 2023, 7:50 AM

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huh, it should work then

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something's not right

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works on my machine ™️

lapis knoll Mar 13, 2023, 8:45 AM

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Using ES2022 if matters, anything else I can provide

lapis knoll Mar 13, 2023, 3:12 PM

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So, anyone got some suggestions?

#Executing a function from a string using dynamic import