tryit

Convert a function to an error-first function

Usage

Error-first callbacks were cool. Using mutable variables to hoist state when doing try/catch was not cool.

The tryit function let’s you wrap a function to convert it to an error-first function. Works for both async and sync functions.

import * as 
import _
_ from 'radashi'

const 
const api: {
    users: {
        find: (id: number) => Promise<any>;
        throw: Error;
    };
}
api = {
  
users: {
    find: (id: number) => Promise<any>;
    throw: Error;
}
users: {
    
find: (id: number) => Promise<any>
find: async (
id: number
id: number) => 
id: number
id < 3 ? { 
id: number
id, 
name: string
name: 'Alice' } : 
throw: Error
throw new 
var Error: ErrorConstructor
new (message?: string) => Error
Error('Not found'),
  },
}
const 
const userIdA: 1
userIdA = 1
const 
const userIdB: 3
userIdB = 3

const [
const errA: Error | undefined
errA, 
const userA: any
userA] = await 
import _
_.
tryit<[id: number], Promise<any>, Error>(func: (id: number) => Promise<any>): (id: number) => _.ResultPromise<any, Error>
export tryit
A helper to try an async function without forking the control flow.
Returns an error-first callback-like array response as [Error, result]
tryit(
const api: {
    users: {
        find: (id: number) => Promise<any>;
        throw: Error;
    };
}
api.
users: {
    find: (id: number) => Promise<any>;
    throw: Error;
}
users.
find: (id: number) => Promise<any>
find)(
const userIdA: 1
userIdA) // [null, { id: 1, name: 'Alice' }]
const [
const errB: Error | undefined
errB, 
const userB: any
userB] = await 
import _
_.
tryit<[id: number], Promise<any>, Error>(func: (id: number) => Promise<any>): (id: number) => _.ResultPromise<any, Error>
export tryit
A helper to try an async function without forking the control flow.
Returns an error-first callback-like array response as [Error, result]
tryit(
const api: {
    users: {
        find: (id: number) => Promise<any>;
        throw: Error;
    };
}
api.
users: {
    find: (id: number) => Promise<any>;
    throw: Error;
}
users.
find: (id: number) => Promise<any>
find)(
const userIdB: 3
userIdB) // [Error('Not found'), undefined]

Currying

You can curry tryit if you like.

import * as 
import _
_ from 'radashi'

const 
const findUser: (id: number) => _.ResultPromise<any, Error>
findUser = 
import _
_.
tryit<[id: number], Promise<any>, Error>(func: (id: number) => Promise<any>): (id: number) => _.ResultPromise<any, Error>
export tryit
A helper to try an async function without forking the control flow.
Returns an error-first callback-like array response as [Error, result]
tryit(
const api: {
    users: {
        find: (id: number) => Promise<any>;
        throw: Error;
    };
}
api.
users: {
    find: (id: number) => Promise<any>;
    throw: Error;
}
users.
find: (id: number) => Promise<any>
find)

const [
const err: Error | undefined
err, 
const user: any
user] = await 
const findUser: (id: number) => _.ResultPromise<any, Error>
findUser(
const userId: 1
userId)