ResultT
ts/js users cannot use try-catch as expression so that we have to struggle with complicated runtimes.
ResultT is type-safe runtime wrapping library. Strongly inspired by Kotlin Result implementation.
Install
From npm registry...
npm i resultt
type declaration is included.
class import...
import { Resultt } from 'resultt';Usage
Try to start from runCatching method. This wraps the result of success or failure.
// sample logic and response interface
interface Response {
data: string
}
class Service {
execute(value: string): Response {
return {data: value};
}
}
// execute some function and wrap by "runCatching"
const result: Result<Response> = Result.runCatching(() => {
return new Service().execute('execution');
})
.onSuccess((v) => {
console.log(`response => ${v}`);
return v
});
.onFailure((it: Error) => {
console.error(it);
return {
data: 'DEFAULT'
};
});
// You may get the value of execute by "get" functions as declarative.
const v1 = result.getOrThrow(); // => success ... { data: execution }
const v2 = result.getOrDefault({
data: 'OTHER'
});
// You can process as commandly.
let v;
if (result.isSuccess()) {
v = result.getOrThrow();
}
// Map the result to another map by fold.
const folded: number = Result.runCatching(() => {
return new Service().execute('execution');
})
.fold(
(data: Response) => {
console.log(data);
return data.data.length;
},
(it: Error) => {
console.log(it);
return 0;
},
);
console.log(folded); // => 9
// Or, shorthand for fold with getOrElse
const n: number = Result.runCatching(() => {
return new Service().execute('execution');
})
.getOrElse((it: Error) => {
console.log(it);
return 0;
},
);
console.log(n); // => 9For more info...
Full class documentation is here: docs