But that doesn't seem like the proper way to do it..
That is indeed the proper way to do it (or at least a proper way to do it). This is a key aspect of promises, they're a pipeline, and the data can be massaged by the various handlers in the pipeline.
Example:
const promises = [_x000D_
new Promise(resolve => setTimeout(resolve, 0, 1)),_x000D_
new Promise(resolve => setTimeout(resolve, 0, 2))_x000D_
];_x000D_
Promise.all(promises)_x000D_
.then(data => {_x000D_
console.log("First handler", data);_x000D_
return data.map(entry => entry * 10);_x000D_
})_x000D_
.then(data => {_x000D_
console.log("Second handler", data);_x000D_
});(catch handler omitted for brevity. In production code, always either propagate the promise, or handle rejection.)
The output we see from that is:
First handler [1,2] Second handler [10,20]
...because the first handler gets the resolution of the two promises (1 and 2) as an array, and then creates a new array with each of those multiplied by 10 and returns it. The second handler gets what the first handler returned.
If the additional work you're doing is synchronous, you can also put it in the first handler:
Example:
const promises = [_x000D_
new Promise(resolve => setTimeout(resolve, 0, 1)),_x000D_
new Promise(resolve => setTimeout(resolve, 0, 2))_x000D_
];_x000D_
Promise.all(promises)_x000D_
.then(data => {_x000D_
console.log("Initial data", data);_x000D_
data = data.map(entry => entry * 10);_x000D_
console.log("Updated data", data);_x000D_
return data;_x000D_
});...but if it's asynchronous you won't want to do that as it ends up getting nested, and the nesting can quickly get out of hand.