Ecosyste.ms: Awesome
An open API service indexing awesome lists of open source software.
https://github.com/martinohmann/promise
Implementation of the Promises/A+ Standard in Go
https://github.com/martinohmann/promise
golang promise promise-instrumentation promise-resolution promiseaplus
Last synced: about 1 month ago
JSON representation
Implementation of the Promises/A+ Standard in Go
- Host: GitHub
- URL: https://github.com/martinohmann/promise
- Owner: martinohmann
- License: mit
- Created: 2019-12-20T13:45:12.000Z (about 5 years ago)
- Default Branch: master
- Last Pushed: 2020-01-02T16:45:14.000Z (about 5 years ago)
- Last Synced: 2024-07-30T20:04:13.182Z (5 months ago)
- Topics: golang, promise, promise-instrumentation, promise-resolution, promiseaplus
- Language: Go
- Homepage:
- Size: 74.2 KB
- Stars: 0
- Watchers: 3
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
Promise
=======
[](https://travis-ci.org/martinohmann/promise)
[](https://codecov.io/gh/martinohmann/promise)
[](https://godoc.org/github.com/martinohmann/promise)
[](https://goreportcard.com/report/github.com/martinohmann/promise)
Initially this started out as an experiment to better understand the inner workings of
JavaScript promises and how this can be implemented from scratch in go.
The result is a promise implementation which follows the [Promises/A+
Standard](https://promisesaplus.com/) and comes with the following additional
features:
* Waiting for promise resolution.
* Panics during promise resolution cause the promise to be rejected with the
panic message.
* Nested promise resolution.
* `Race`, `All`, `Any` and `AllSettled` extensions to handle the parallel
resolution of multiple promises.
* Promise pooling. See the [`promise.Pool`
documentation](https://godoc.org/github.com/martinohmann/promise#Pool)
and the [pooling example](_examples/dns-lookup/pooled/main.go).
* Promise instrumentation for tracing, logging and debugging. See the
[`instrumented` package
documentation](https://godoc.org/github.com/martinohmann/promise/instrumented)
for more information.
Head over to the [`promise`
godoc](https://godoc.org/github.com/martinohmann/promise) for the API
documentation.
Installation
------------
```
go get -u github.com/martinohmann/promise
```
Usage
-----
Check out the examples in the [_examples/](_examples/) directory to see promises in action.
### Simple example
```go
package main
import (
"errors"
"fmt"
"math/rand"
"time"
"github.com/martinohmann/promise"
)
func init() {
rand.Seed(time.Now().UnixNano())
}
func main() {
p := promise.New(func(resolve promise.ResolveFunc, reject promise.RejectFunc) {
// simulate some computation
sleepDuration := time.Duration(rand.Int63n(2000)) * time.Millisecond
time.Sleep(sleepDuration)
fmt.Printf("computation took %s\n", sleepDuration)
// inject some random errors
if rand.Int63n(2) == 0 {
reject(errors.New("computation failed"))
return
}
// simulate computation result
resolve(rand.Int63())
}).Then(func(val promise.Value) promise.Value {
fmt.Printf("computation result: %d\n", val.(int64))
return val
}).Catch(func(err error) promise.Value {
fmt.Printf("error during computation: %v\n", err)
return err
})
// Wait for the promise resolution to be complete, that is: either fulfillment or rejection.
val, err := p.Await()
if err != nil {
fmt.Printf("Promise rejected with error: %v\n", err)
} else {
fmt.Printf("Promise fulfilled with value: %d\n", val.(int64))
}
}
```
License
-------
The source code of promise is released under the MIT License. See the bundled
LICENSE file for details.