Using promises and continuations

Asked Jul 20 '20 at 05:45

Active Jul 20 '20 at 05:50

Viewed 24 times

I have looked at many examples of Promises and Continuations but have not found a consistently working pattern.

Here is an attempt to use a pair of encryption related methods:

async function makeAesGcmKeys() {
    let key = await crypto.subtle.generateKey(
        {
            name: "AES-GCM",
            length: 256
        },
        true,
        ["encrypt", "decrypt"]
    );   
    let exported = key.then( k => { crypto.subtle.exportKey('raw',k)})
    return [key,exported]
}

makeAesGcmKeys().then((k,e) => { 
   console.log(`in continuation: exported=${e}`); 
   return [k,e]
}).then( (key,exported) => {
    console.log(`main: ${exported}`)
});

This results in a Promise being returned. I need the resolved result not the Promise. I have tried various permutations on the above but they also return a Promise. Pointers appreciated.

edited Jul 20 '20 at 05:50

Sebastian Kaczmarek

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asked Jul 20 '20 at 05:45

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Have you tried with `await key.then(...)`? – Sebastian Kaczmarek Jul 20 '20 at 05:48
@SebastianKaczmarek I added that and still do not see anything printed on Console – WestCoastProjects Jul 20 '20 at 05:50
`.then()`'s callback takes only one argument. If you have returned `[key,exported]` in your function, then you need to treat `k` in `.then()` as an array. Try printing `k[1]` instead of `e` (while still having `await key.then(...)`). – Sebastian Kaczmarek Jul 20 '20 at 05:53

Using promises and continuations

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