Promisesque

Lazily create a promise only when async values are used, otherwise sync all the way down.

     

npm: npm install promisesque --save
cdn: https://cdn.jsdelivr.net/npm/promisesque@latest/src/index.js

Although typically a bad idea, there exists a handful of legitimate cases where outputting a promise should be dependent on whether the inputs are promise values, yet still being able to handle both with the same interface.

import * as prq from 'promisesque';

const value = 'foo';
const values = [value, 'bar'];

prq.get(value, ok, error); // foo
prq.all(values, ok, error); // [foo, bar]
prq.race(values, ok, error); // foo

const valueP = Promise.resolve(value);
const valuesP = [valueP, Promise.resolve('bar')];

await prq.get(valueP, ok, error); // foo
await prq.all(valuesP, ok, error); // [foo, bar]
await prq.race(valuesP, ok, error); // foo

Note that the sync version of prq.race is somewhat pointless, as the first value in the array will always win. Nevertheless it is included for compatibility reasons. Also note that currently the finally clause is not supported.

Errors are only caught when passing an error function as the third argument. Each error function receives the error that was thrown in the ok function.