Home > @pearden/promise-props > propsDeep
The propsDeep() function takes an enumerable object as input and returns a single Promise. This returned promise fulfills when all the input’s promise properties fulfill (regardless of the property level) (including when an empty iterable is passed), with an object of the fulfillment values as properties. It rejects when any of the input’s property rejects, with this first rejection reason.
Signature:
declare function propsDeep<T extends object, K extends keyof T>(obj: T): Promise<Record<K, Awaited<T[K]>>>;
| Parameter | Type | Description |
|---|---|---|
| obj | T | An object with promise properties |
Returns:
Promise<Record<K, Awaited<T[K]>>>
A promise that is:
* Already fulfilled, if the object passed has no enumerable properties
* Asynchronously fulfilled, when promise properties of all levels fulfill. The fulfillment value is an object with the promise properties’ fulfillment values, keeping the object structure. For those none promise properties, their values will still be kept. For none promise objects of any level, they will be shallow copied to the result object except for their promise properties. For nonenumerable properties, their values will be ignored.
* Asynchronously rejected, when any promise in the given object rejects. The rejection reason is the rejection reason of the first promise that was rejected.
A rejected example
const obj = {
sub: {
reject: Promise.reject("rejected")
}
} ;
await Promise.props(obj) ;
This will get a promise rejected with reason “rejected”
comprehensive demo for props() function
const obj = {
name: "promise",
age: Promise.resolve(123),
nest: Promise.resolve(Promise.resolve("nest")),
sub: {
country: Promise.resolve("node"),
}
} ;
Object.defineProperty(obj, "nonEnumerable", { value: "nonEnumerable", enumerable: false}) ;
await Promise.props(obj) ;
The result will be like this:
result = {
name: "promise",
age: 123,
nest: "nest",
sub: {
country: "node"
}
}