Pg-promise: ES6 Generators use

[LoiKos]

Hi,

I'm working with pg-promise and I read your wiki and I see the section in chaining query with ES6.

I have to provide update after verify, that the object already exist in the database. Which way is the best to deal with it? using generator like this :

return db.task(function* (t){
let product = yield t.oneOrNone("select * from products where refproduct = $1",[id])
//... some task
return yield t.one('update products set name = ${name}, picture = ${picture}  where refproduct = ${refproduct} returning *', product)
        })

Or like that :

return db.task(t = >{
  return t.oneOrNone("select * from products where refproduct = $1",[id])
  .then( data => {
        return t.one('update products set name = ${name}, picture = ${picture}  where refproduct =         ${refproduct} returning *', product)
    })
})

[vitaly-t]

Which way is the best

Whichever you like, the result is the same.

[vitaly-t]

@LoiKos Note that your example is generally a bad one, because you use oneOrNone first, which can resolve with 1 row or null, as per the API, and you use it without checking if it is null.

[LoiKos]

That because I don't paste all the code, this is the complete function :

update(id, json) {
        return db.task(function* (t){

            let product = yield t.oneOrNone("select * from products where refproduct = $1",[id])

            if(!product){
                return Promise.reject(ApiError.notFound())
            }
            for(key in json){
                if (Object.keys(product).includes(key) && ["refproduct","creationdate"].indexOf(key) == -1){
                        product[key] = json[key]
                } else {
                    return Promise.reject(ApiError.notFound("One key in the json body is not known or can't be modified"))
                }
            }
            return yield t.one('update products set name = ${name}, picture = ${picture}  where refproduct = ${refproduct} returning *', product)
        })
    }

[vitaly-t]

ok, but now you show bad code style for ES6 generators.

When inside generators, you should use throw instead of return Promise.reject :wink:

I will work either way, because pg-promise is so smart, but in general it is considered a bad style ;)

[LoiKos]

I'm not familiar with generator I can use it like this ?

if(!product){
    throw(ApiError.notFound())
} 

[vitaly-t]

if(!product){
    throw ApiError.notFound();
}

[LoiKos]

Okay thanks you for your answers :)