madmaid / monoflow

A monadic interface for handling errors in JS

Monoflow

A monadic interface for handling errors in JS

What is it?

Monoflow provides one Workflow class that makes you easier to deal with combine functions, error handlings, and provides lazy evaluation.

Examples

Example 1: Create Workflow instance

import { Workflow } from "monoflow"

const workflow = Workflow.create((x: number) => x + 1);

console.log(workflow.run(2)); // Output: 3

That's it. Note that you need to explicit type of input type.

Example 2: Chain functions with .then()

const workflow = Workflow.create((x: number) => x + 1)
  .then((x) => x * 2)
  .then((x) => x + 1);

console.log(workflow.run(1)); // Output: 5

Example 3: Deal with errors

const workflow = Workflow.create((x: number) => x + 1)
  .then((x) => x * 2)
  .then((x) => x + 1)
  .then((_) => throw new Error("error!"))
  .else((err) => err.message);

console.log(workflow.run(1)); // Output: "error!"

Note that you can put .else() anyware. So as you can see below, you can get back to the function mapped by .then()

const workflow = Workflow.create((x: number) => x + 1)
  .then((x) => x * 2)
  .then((x) => x + 1)
  .then((_) => throw new Error("error!"))
  .else((err) => err.message);
  .then((x: string) => x + "!")

console.log(workflow.run(1)); // Output: "error!!"

Example 4: Combine workflows

You can combine multiple workflows like this:

const workflow1 = Workflow.create((_) => {
  throw new Error("error")
});
const workflow2 = Workflow.create((_) => undefined)
  .else((err) => err.message);
const workflow3 = workflow1.combine(workflow2);
console.log(workflow3.run(undefined)); // Output: "error"

Authors

Maintainer

@minamorl

Core Contributors

@wavebeem