Malle

Malle (short for Malleable) is a fast, flexible, developer-first argument parser for modern JavaScript and Node.js.

It allows functions to accept arguments in any order, intelligently infer intent, and validate inputs without relying on rigid, positional APIs.

Wiki https://github.com/EkaanshPC/malle/wiki

Github https://github.com/EkaanshPC/malle

Features

• Order-agnostic arguments

  Accept arguments in any order without sacrificing clarity or safety.

• Type inference & guessing

  Automatically matches arguments based on type, name, and configurable rules.

• Composable & extensible

  Define schemas, constraints, defaults, and custom resolvers.

• Flexible modes

  Switch between strict and loose parsing modes to control tolerance and ordering.

Quick Example

import malle from "@briklab/malle";

function calculate(...args) {
  const {
    Number1,
    Number2,
    Mode,
    __DidSucceed
  } = malle({ mode: "strict" }).expect(
    { name: "Number1", type: "number" },
    { name: "Number2", type: "number" },
    { name: "Mode", type: "string" }
  ).guess(args);

  if (!__DidSucceed) return;

  const [a, b, c] = [Number1, Number2, Mode];

  return c === "subtract" ? a - b
       : c === "add"      ? a + b
       : c === "divide"   ? a / b
       :                    a * b;
}

Optional-argument example

// 'Mode' is optional — if not provided it will be `undefined` and won't
// consume positional args that follow.
import malle from "@briklab/malle";

const res = malle().expect(
  { name: "Mode", type: "string", optional: true },
  { name: "count", type: "number" }
).guess(42);

// result: { Mode: undefined, count: 42 }
console.log(res);