Is there a better way of writing a function with two async?

user_17895626 0
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I have this function:

private async get(iD: string): Promise<Function> {
        return async () => {
            const tallConfig = await longCrudService.getHalf(iD);
            const stream: Stream = tallConfig.stream;

            const response = this.createUrl(tallConfig, stream);
            return response;
        };
    }

Is there a way I could re-write this but without using double async, like is there a way I could re-write this by using only the async of the function, and removing the inner async?

async-await typescript asynchronous javascript
2 Answers

The only decent use of async is when you need to await directly inside. Since you aren't doing so for the outer function, you can remove it - only the inner function is making use of an await.

private get(iD: string): Promise <Function> => async () => {
    const tallConfig = await longCrudService.getHalf(iD);
    const stream: Stream = tallConfig.stream;
    const response = this.createUrl(tallConfig, stream);
    return response;
}

You could also remove the asyncs entirely if you wanted, in exchange for .then.

private get(iD: string): Promise <Function> => () => longCrudService.getHalf(iD)
    .then(tallConfig => this.createUrl(tallConfig, tallConfig.stream));
user_95152070

There's no need for an inner function you can rewrite as such:

private async get(iD: string): Promise<Function> {
    const tallConfig = await longCrudService.getHalf(iD);
    const stream: Stream = tallConfig.stream;

    return this.createUrl(tallConfig, stream);
}

Make sure that the caller does not need another function call as this would return a promise as specified on your function signature.

user_25594490
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