Dynamic Typing

[gilded robin]

Why is in case "ERROR" the variable "error" not strictly typed as "Error" and still either "string" or "Error"?

type Levels = {
    ERROR: [error: Error];
    WARNING: [message: string];
    INFO: [message: string];
};

public log<K extends keyof Levels>(level: K, ...args: Levels[K]): void {
    const date = new Date();

    let message: string | null = null;

    switch (level) {
        case "ERROR": {
            const error = args[0];
            message = `[${Moment(date).format("YYYY-MM-DD HH:mm:ss")}] [${level}] - ${error.message}\n\n`;
        }
    }
}

[glacial bison]

because narrowing level doesn't narrow args

those are 2 different objects

even tho they are linked, TS can't really understand it

you could cast error as Error

or simply refractor the code to avoid the problem entierly (the code isn't ideal imho)

[gilded robin]

What would be a better approach?

[glacial bison]

making different methods, one per level

[gilded robin]

Okay, let me do that.

[gilded robin]

Like that? ```ts
public log(level: "ERROR", content: Error): void;
public log(level: "WARNING", content: string): void;
public log(level: "INFO", content: string): void;
public log(level: "ERROR" | "WARNING" | "INFO", content: Error | string): void

[glacial bison]

that's overload

it would also work

[gilded robin]

Ah, now I know what you mean.

[gilded robin]

Nah, also has the same issue.

[glacial bison]

I was mainly talking about

public log() {}
public warn() {}
public error() {}