tiny-guards 💂

> A tiny library for advanced typescript guarding

- 🪶 lightweight
- 🍃 tree-shakable
- 🧱 composable
- 👮 type-safe
- 🔗 zero dependencies
- 🌚 dead simple

``bash
npm install tiny-guards
`

$3

`typescript
import {
asserts,
gt,
isNumber,
isString,
maxLen,
oneOf,
optional,
refine,
shape,
Guard,
tinyGuards,
} from "tiny-guards";

const isNaturalNumber = refine(isNumber, gt(0), Number.isSafeInteger);
const isShortString = refine(isString, maxLen(16));
const isAccountType = oneOf(["reader", "publisher", "moderator"]);

const isUser = shape({
id: isNaturalNumber,
username: isShortString,
accountType: isAccountType,
firstName: optional(isString),
lastName: optional(isString),
});

type User = GuardInfer;

function doSomething(v: unknown) {
try {
asserts(v, isUser);

v.id; // ✅
v.username; // ✅
} catch (error) {
console.error(error);
// TinyGuardsError: validation failed
// [shape]: value at key "id" is blocked by guard "refine"
// [refine]: value is blocked by refinement "gt" (index "0")
}
}

function doSomething(v: unknown) {
if (isUser(v)) {
v.id; // ✅
v.username; // ✅
} else {
isUser.error;
// TinyGuardsError: validation failed
// [shape]: value at key "id" is blocked by guard "refine"
// [refine]: value is blocked by refinement "gt" (index "0")
}
}
``