MakeSafeFunc

Finally be sure your functions don't throw

MakeSafeFunc was created to wrap functions I'm not sure can throw and returning a simple Result type by utilizing neverthrow under the hood

Why MakeSafeFunc ?

MakeSafeFunc is designed to bring make the Result Types and functional Principles that neverthrow is working to make available to Typescript Developers, To legacy projects.

MakeSafeFunc is for developers working in legacy where it wouldn't be worth it to attempt a full conversion to Result types instead of focusing on business logic. Instead developers can work on the code they should be working on while protecting themselves from the errors of:

• Third-Party Code
• Internal Code

By definition makeSafeFunc is a simple function that you can probably implement in your code yourself or even simply copy right from this package into your existing source tree

import {functionFromLegacy} from "@acme/legacy";
import {makeSafeFunc} from "@disgruntleddevs/make-safe-func";

const result=makeSafeFunc(functionFromLegacy)(params,from,legacyCode)

// all the niceties... none of the refactoring work
result.match();
result.unwrapOr();
result.isOk();
result.value;
result.error;
result.map()

Examples

Synchronous Functions

import {makeSafeFunc} from "make-safe-func";

function unsafeDivide(a:number,b:number){
  if(b===0) throw new Error("Divide by Zero Error");
  return a/b
}

const safeDivide=makeSafeFunc(unsafeDivide);

safeDivide(1/2).match(console.log,console.error);

Asynchronous Functions

import {makeSafeFunc} from "make-safe-func";

async function unsafeFetch(url:string){
  const result=await fetch(url);

  return result
}

const safeFetch=makeSafeFunc(unsafeFetch);

safeFetch("https://google.com").match(console.log,console.error);

Matching on Result

import {makeSafeFunc} from "make-safe-func";

async function unsafeFetch(url:string){
  const result=await fetch(url);

  return result
}

const safeFetch=makeSafeFunc(unsafeFetch);

safeFetch("https://google.com").match(console.log,console.error);

Unwrapping Result with .unwrapOr

import {makeSafeFunc} from "make-safe-func";

async function unsafeFetch(url:string){
  const result=await fetch(url);

  return result
}

const safeFetch=makeSafeFunc(unsafeFetch);

// used to return default values in the event
// of a failure
safeFetch("https://google.com").unwrapOr("failed");

Mapping over result

import {makeSafeFunc} from "make-safe-func";

function unsafeDivide(a:number,b:number){
  if(b===0) throw new Error("Divide by Zero Error");
  return a/b
}

const safeDivide=makeSafeFunc(unsafeDivide);

const increment=(v:number)=>v+1;

// perform a transformation on the
// result and receive a Result of the Transformation
const res=safeDivide(1/2).map(increment)

.andThen

import {makeSafeFunc} from "make-safe-func";

function unsafeDivide(a:number,b:number){
  if(b===0) throw new Error("Divide by Zero Error");
  return a/b
}

const safeDivide=makeSafeFunc(unsafeDivide);

const increment=(v:number)=>v+1;

// perform a transformation on the
// result that might fail. You must return a new Result
// Value
const res=safeDivide(1/2).andThen()

Importing Third-Party Code

import {makeSafeFunc} from "@disgruntleddevs/make-safe-func";
import {someLibraryFunction} from "@third-party/library";

const safeLibraryFunction=makeSafeFunc(someLibraryFunction);

const result=safeLibraryFunction(params,for,func).unwrapOr("default value")

console.log(result);

The MakeSafeFunc docs are sparse because most of it's power is derived from neverthrow so their documentation will be very helpful These are simply examples of the context makeSafeFunc is useful for