Theo's Typesafe Cult•16mo ago

get rid of Symbol iterator in autocomplete

Hi TS nerds, I'm in dire need of help; For a bit of context, I have a function that returns a tuple: const [hej, do] = myFunc(), and I'm looking to allow an object being returned by the same function: const obj = myFunc() // obj.hej and obj.do exist. for WAY more accurate code, see: https://github.com/bdsqqq/try/pull/10 My solution of choice rn would be:

export const trytm = async <T>(
    promise: Promise<T>,
): Promise<TryResult<T>> => {
    const getResult = (data: T | null, error: Error | null) => ({ 
        data, 
        error,  
        [Symbol.iterator]: function* () {
            yield this.data;
            yield this.error;
        }
    })
    try {
        const data = await promise;
        return getResult(data, null);
    } catch (throwable) {
        if (throwable instanceof Error) {
            return getResult(null, throwable);
        }
        
        throw throwable;
    }
};

export const trytm = async <T>(
    promise: Promise<T>,
): Promise<TryResult<T>> => {
    const getResult = (data: T | null, error: Error | null) => ({ 
        data, 
        error,  
        [Symbol.iterator]: function* () {
            yield this.data;
            yield this.error;
        }
    })
    try {
        const data = await promise;
        return getResult(data, null);
    } catch (throwable) {
        if (throwable instanceof Error) {
            return getResult(null, throwable);
        }
        
        throw throwable;
    }
};

But this makes the autocomplete of the object include data, error AND Symbol... Is there any way to not have Symbol there??

1 Reply

bedesqui•16mo ago

A proposed solution was:

class TryResult<T extends any | null> {
    private [Symbol.iterator] = function* (): IterableIterator<[T | null, Error | null]> {
        yield [this.data, this.error];    
    }
    public data: T | null;
    public error: Error | null;

    constructor(data: T, error: Error | null) {
        this.data = data;
        this.error = error;
    }
}

export const trytm = async <T>(
    promise: Promise<T>,
): Promise<TryResult<T | null>> => {
    
    try {
        const data = await promise;
        return new TryResult(data, null);
    } catch (throwable) {
        if (throwable instanceof Error) {
            return new TryResult(null, throwable);
        }
        throw throwable;
    }
};

const mockPromise = new Promise<string>((resolve) => {
    setTimeout(() => {
        resolve('hello');
    }, 1000);
})

async function main() {
    const [[data, error]] = await trytm(mockPromise);
    const result = await trytm(mockPromise);
}

class TryResult<T extends any | null> {
    private [Symbol.iterator] = function* (): IterableIterator<[T | null, Error | null]> {
        yield [this.data, this.error];    
    }
    public data: T | null;
    public error: Error | null;

    constructor(data: T, error: Error | null) {
        this.data = data;
        this.error = error;
    }
}

export const trytm = async <T>(
    promise: Promise<T>,
): Promise<TryResult<T | null>> => {
    
    try {
        const data = await promise;
        return new TryResult(data, null);
    } catch (throwable) {
        if (throwable instanceof Error) {
            return new TryResult(null, throwable);
        }
        throw throwable;
    }
};

const mockPromise = new Promise<string>((resolve) => {
    setTimeout(() => {
        resolve('hello');
    }, 1000);
})

async function main() {
    const [[data, error]] = await trytm(mockPromise);
    const result = await trytm(mockPromise);
}

But this makes the destructures look like like [[data, error]] Fineeeeeeee, the symbol iterator is supposed to be there, removing it would be lying to the user

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get rid of Symbol iterator in autocomplete