Catch-flow NPM

Catch-Flow

A simple, lightweight library offering iterable try-catch decorators.

npm install catch-flow

import cf from "catch-flow";
const { catchSync, catchAsync, catchMap, catchFlow } = cf;

Note: catch-flow does not currently support commonJS require()

catchSync

Wrap any pre-existing synchronous function with a catch decorator:

const myNormalFunction = (start, end) => {
  if (start > end) throw Error("What have you done?!");
  if (start === end) return;
  console.log(start);
  return myNormalFunction(start + 1, end);
};
const catchFlowFunc = catchSync(myNormalFunction);
// Pass arguments the same
catchFlowFunc(3, 9);

// Catches and prints error
catchFlowFunc(9, 3);

Or wrap and define at once:

const myFunctionWrapped = catchSync((start, end) => {
  if (start > end) throw Error("What have you done?!");
  if (start === end) return;
  console.log(start);
  return myFunctionWrapped(start + 1, end);
});

myFunctionWrapped(3, 19);

catchAsync

catchAsync wraps a Promise-returning function. This is it's only functional difference from catchSync.

const asyncJob = catchAsync(
  (msg) =>
    new Promise((resolve, reject) => {
      resolve(`Echo: ${msg}`);
      if (!msg) {
        reject("Promise rejected.");
      }
    })
);

const res = await asyncJob("echo echo ... ");
console.log(res);

const rejected = await asyncJob("");
console.log(rejected);

catchMap - Async

catchMap is functionally similar to Promise.all, but wraps every promise in a try-catch block

// Simulate some promises:
// ===
const stepOne = async (msg) => setTimeout(() => log(msg), 1000);
const stepTwo = async (msg) => setTimeout(() => log(msg), 1500);
const stepThree = async (msg) => setTimeout(() => log(msg), 3000);
const stepFour = async (...msgs) =>
  setTimeout(() => msgs.forEach((msg) => log(msg)), 5000);
const stepFive = async () => setTimeout(() => log("Sincerely"), 6000);
// ===

const funks = [stepOne, stepTwo, stepThree, stepFour, stepFive];
// Build custom async-catch function by passing array of functions to decorator:
const messageMap = catchMap(funks);

// === Each function takes it's arguments as an array, in the left-to-right order of the functions passed.
// === Note that one must pass an empty array for a function without arguments:
await messageMap(["Come"], ["home,"], ["please."], ["I", "miss", "you"], []);
==================
// -> Promises are returned in the order that they are resolved.
// -> Errors are thrown in the order that they are caught.
==================