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https://github.com/donatorsky/go-promise
Promise library for Go.
https://github.com/donatorsky/go-promise
go golang promise promise-library
Last synced: 2 days ago
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Promise library for Go.
- Host: GitHub
- URL: https://github.com/donatorsky/go-promise
- Owner: donatorsky
- License: mit
- Created: 2022-02-10T10:56:18.000Z (almost 3 years ago)
- Default Branch: main
- Last Pushed: 2024-02-14T22:34:11.000Z (9 months ago)
- Last Synced: 2024-02-14T23:31:59.731Z (9 months ago)
- Topics: go, golang, promise, promise-library
- Language: Go
- Homepage:
- Size: 52.7 KB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# Go Promise
Promise library for Go.
[](https://github.com/donatorsky/go-promise/blob/main/LICENSE)
[](https://github.com/donatorsky/go-promise/actions?query=branch%3Amain)
[](https://codecov.io/gh/donatorsky/go-promise)
## Installation
```shell
go get github.com/donatorsky/go-promise
```
## Example
```go
package main
import (
"errors"
"fmt"
"time"
"github.com/donatorsky/go-promise"
)
func main() {
p := promise.NewPromise(func(resolve Resolver, reject Rejector) {
time.Sleep(time.Millisecond * 1000)
resolve("foo")
reject(errors.New("error from constructor"))
fmt.Println("Constructor: actions after promise resolution")
})
p.
Finally(func() {
fmt.Println("Finally(1) <- constructor")
}).
Then(func(value interface{}) (result interface{}, err error) {
fmt.Println("Then() <- Finally(1) <- constructor:", value)
return 000, errors.New("error from Then()")
}).
Catch(func(reason error) {
fmt.Println("Catch() <- Then() <- Finally(1) <- constructor:", reason)
}).
Finally(func() {
fmt.Println("Finally(2) <- Catch() <- Then() <- Finally(1) <- constructor")
})
p.
Then(func(value interface{}) (result interface{}, err error) {
fmt.Println("Then() returning resolved Promise <- constructor:", value)
time.Sleep(time.Millisecond * 150)
return promise.Resolve("Immediately resolved Promise"), nil
}).
Then(func(value interface{}) (result interface{}, err error) {
fmt.Println("Then() returning pending Promise <- Then() returning resolved Promise <- constructor:", value)
time.Sleep(time.Millisecond * 150)
return promise.NewPromise(func(resolve Resolver, reject Rejector) {
time.Sleep(time.Millisecond * 250)
resolve("Inner Promise")
reject(errors.New("inner error"))
}), nil
}).
Catch(func(reason error) {
fmt.Println("Catch() <- Then() returning pending Promise <- Then() returning resolved Promise <- constructor:", reason)
}).
Then(func(value interface{}) (result interface{}, err error) {
fmt.Println("Then() <- Catch() <- Then() returning pending Promise <- Then() returning resolved Promise <- constructor:", value)
return nil, nil
})
p.
Catch(func(reason error) {
time.Sleep(time.Millisecond * 101)
fmt.Println("Catch() <- constructor:", reason)
}).
Then(func(value interface{}) (interface{}, error) {
time.Sleep(time.Millisecond * 101)
fmt.Println("Then() <- Catch() <- constructor:", value)
return 111, nil
}).
Then(func(value interface{}) (interface{}, error) {
time.Sleep(time.Millisecond * 101)
fmt.Println("Then() <- Then() <- Catch() <- constructor:", value)
return nil, nil
})
p.
Then(func(value interface{}) (interface{}, error) {
time.Sleep(time.Millisecond * 102)
fmt.Println("Then(1a) <- constructor:", value)
return 222, nil
}).
Catch(func(reason error) {
time.Sleep(time.Millisecond * 102)
fmt.Println("Catch() <- Then(1a) <- constructor:", reason)
}).
Then(func(value interface{}) (interface{}, error) {
time.Sleep(time.Millisecond * 101)
fmt.Println("Then() <- Catch() <- Then(1a) <- constructor:", value)
return 333, nil
})
p.
Then(func(value interface{}) (interface{}, error) {
time.Sleep(time.Millisecond * 103)
fmt.Println("Then(1b) <- constructor:", value)
return 444, nil
}).
Then(func(value interface{}) (interface{}, error) {
time.Sleep(time.Millisecond * 103)
fmt.Println("Then() <- Then(1b) <- constructor:", value)
return 555, nil
}).
Catch(func(reason error) {
time.Sleep(time.Millisecond * 102)
fmt.Println("Catch() <- Then() <- Then(1b) <- constructor:", reason)
}).
Then(func(value interface{}) (interface{}, error) {
time.Sleep(time.Millisecond * 101)
fmt.Println("Then() <- Catch() <- Then() <- Then(1b) <- constructor:", value)
return 666, nil
})
time.Sleep(time.Second * 3)
fmt.Println(p)
fmt.Println(promise.Resolve(5))
fmt.Println(promise.Reject(errors.New("nope")))
}
```
The output:
```text
Constructor: actions after promise resolution
Finally(1) <- constructor
Then() returning resolved Promise <- constructor: foo
Then(1a) <- constructor: foo
Then(1b) <- constructor: foo
Then() <- Finally(1) <- constructor: foo
Catch() <- Then() <- Finally(1) <- constructor: error from Then()
Finally(2) <- Catch() <- Then() <- Finally(1) <- constructor
Then() returning pending Promise <- Then() returning resolved Promise <- constructor: Immediately resolved Promise
Then() <- Catch() <- constructor: foo
Then() <- Then() <- Catch() <- constructor: 111
Then() <- Catch() <- Then() returning pending Promise <- Then() returning resolved Promise <- constructor: Inner Promise
Then() <- Catch() <- Then(1a) <- constructor: 222
Then() <- Then(1b) <- constructor: 444
Then() <- Catch() <- Then() <- Then(1b) <- constructor: 555
&{fulfilled [] [] foo }
&{fulfilled [] [] 5 }
&{rejected [] [] 0xc000180040}
```