Lodash's .mapValues but for async functions

map-values-async.js

const mapValuesAsync = (obj, asyncFn) => {
  const keys = Object.keys(obj);
  const promises = keys.map(k => {
    return asyncFn(obj[k]).then(newValue => {
      return {key: k, value: newValue};
    });
  });
  return Promise.all(promises).then(values => {
    const newObj = {};
    values.forEach(v => {
      newObj[v.key] = v.value;
    });
    return newObj;
  });
};

Thanks! I needed that!

Thanks!

Nice, Thank you :). I tried to make it a bit more readable. This is what I came up with:

async function mapValuesAsync(obj, asyncFn) {
    const promises = Object.entries(obj).map(([ key, value ]) => {
        return asyncFn(key, value).then(newValue => ({ [ key ]: newValue }));
    });

    return Promise.all(promises).then(result => _.assign(...result));
};

I suggest you my own version :

function mapValuesAsync(collection, asyncFn) => {
    const promises = Object.entries(collection).map(([ key, value ], index) => {
      return asyncFn(value, key, index, collection).then(resolved => [ key, resolved ]);
    });
    return Promise.all(promises).then(Object.fromEntries);
  }

Nice!!!