@httpx/assert

Assertions and typeguards as primitives

warning: pre-v1, use at your own risks

Install

$ npm install @httpx/assert
$ yarn add @httpx/assert
$ pnpm add @httpx/assert

Features

• 👉  Typeguards and assertions with a consistent style.
• 👉  Assertions with useful default error message.
• 👉  Return weak opaque types for boolean, strings and numbers.
• 👉  Optimized tree-shakability, starts at 56b.
• 👉  Don't leak values in the default assertion error messages.
• 👉  No deps. Node, browser and edge support.

Documentation

👉 Official website, GitHub Readme or generated api doc

• Introduction
  • Consistent style
  • Weak opaque types
  • Assertions error messages
• Usage
  • Type related
    • assertNever
  • Object related
    • isPlainObject
  • Number related
    • isNumberSafeInt
  • Array related
    • ArrayNonEmpty
  • String related
    • StringNonEmpty
    • ParsableSafeInt
    • isParsableStrictIsoDateZ
  • Uuid
    • isUuid
  • Barcode
    • isEan13
  • Network
    • isNetWorkPort
  • Http
    • isHttpMethod
    • isValidHttpMethod
• Bundle size
• Compatibility
• Acknowledgments
• Contributors
• Sponsors

Introduction

Consistent style

Typeguards starts with isXXX and have an assertion counterpart named assertXXX.

isParsableXXX and assertParsableXXX denotes a string.

Weak opaque types

For string, number and boolean the returned type is tagged with a weak opaque type. It can optionally be used to enforce that the value was checked.

For example:

import { assertUuidV7, type UuidV7 } from '@httpx/assert';
import { HttpUnprocessableEntity } from '@httpx/exception';

const persistRecord = async (uuid: UuidV7) => {
  // uuid is compatible with string.
  return await db.raw(`insert into tbl(uuid) values (${uuid})`)
}

const v = 'xxx'; // unknown
assertUuidV7(v, () => new HttpUnprocessableEntity());
// 👉 v is known to be `string & WeakOpaqueContainer<'UuidV4'>`
await persistRecord(v); // will work
await persistRecord('a_string'); // won't

Assertions error messages

When an assertion fail, a native TypeError is thrown by default with a message indicating the requirement and and information about the tested value. As an example:

expect(() => assertUuid('123')).toThrow(
  new TypeError('Value is expected to be an uuid, got: string(length:3)')
);
expect(() => assertUuid(false, undefined, { version: 1 })).toThrow(
  new TypeError('Value is expected to be an uuid v1, got: boolean(false)')
);
expect(() => assertUuidV1(Number.NaN)).toThrow(
  new TypeError('Value is expected to be an uuid v1, got: NaN')
);
expect(() => assertUuidV3(new Error())).toThrow(
  new TypeError('Value is expected to be an uuid v3, got: Error')
);
expect(() => assertUuidV4(new Date())).toThrow(
  new TypeError('Value is expected to be an uuid v4, got: Date')
);
expect(() => assertUuidV5(() => {})).toThrow(
  new TypeError('Value is expected to be an uuid v5, got: function')
);
expect(() => assertUuidV7(() => {})).toThrow(
  new TypeError('Value is expected to be an uuid v7, got: function')
);
//...

Alternatively it's possible to provide either a message or function returning an Error. For example:

import { assertEan13, assertStringNonEmpty } from '@httpx/assert';
import { HttpBadRequest } from '@httpx/exception';

assertEan13('123', 'Not a barcode'); // 👈 Will throw a TypeError('Not a barcode')

const lang = null;
assertStringNonEmpty(lang, () => new HttpBadRequest('Missing language'));

Usage

Type related

assertNever

import { assertNever } from '@httpx/assert';

type PromiseState = 'resolved' | 'rejected' | 'running'
const state: PromiseState = 'rejected';
switch(state) {
  case 'resolved': return v;
  case 'rejected': return new Error();
  default:
    assertNever(state); // 👈 TS will complain about missing 'running' state
    // ☝️ Will throw a TypeError in js.
}

PS: you can use the assertNeverNoThrow with the same behaviour except that it doesn't throw and return the value instead (no runtime error).

Object related

isPlainObject

| Name | Type | Comment | |-------------------------|------------------|---------| | isPlainObject<T?> | PlainObject | | | assertPlainObject<T?> | PlainObject | |

Based on @httpx/plain-object

import { isPlainObject, assertPlainObject } from '@httpx/assert';

// ✅👇 True

isPlainObject({ key: 'value' });          // ✅ 
isPlainObject({ key: new Date() });       // ✅ 
isPlainObject(new Object());              // ✅ 
isPlainObject(Object.create(null));       // ✅ 
isPlainObject({ nested: { key: true} });  // ✅ 
isPlainObject(new Proxy({}, {}));         // ✅ 
isPlainObject({ [Symbol('tag')]: 'A' });  // ✅ 

// ✅👇 (node context, workers, ...)
const runInNewContext = await import('node:vm').then(
    (mod) => mod.runInNewContext
);
isPlainObject(runInNewContext('({})'));   // ✅ 

// ❌👇 False

class Test { };
isPlainObject(new Test())           // ❌ 
isPlainObject(10);                  // ❌ 
isPlainObject(null);                // ❌ 
isPlainObject('hello');             // ❌ 
isPlainObject([]);                  // ❌ 
isPlainObject(new Date());          // ❌ 
isPlainObject(Math);                // ❌ Static built-in classes 
isPlainObject(Promise.resolve({})); // ❌
isPlainObject(Object.create({}));   // ❌

assertPlainObject({})                  // 👈 ✅ true

Usage with generic

import { isPlainObject, assertPlainObject } from '@httpx/assert';

// With generic value (unchecked at runtime!)
type CustomType = {
  name: string;
  deep: {
    yes: boolean | null;
  };
};
const value = {
  name: 'hello',
  deep: {
    yes: true,
  },
} as unknown;

if (isPlainObject<CustomType>(value)) {
  // Notice it's a deep partial to allow autocompletion
  value?.deep?.yes; // 👈  yes will be unknown to reflect that no runtime check was done
}

assertPlainObject<CustomType>(value);

Number related

isNumberSafeInt

import { assertNumberSafeInt, isNumberSafeInt } from '@httpx/assert';

isNumberSafeInt(10n); // 👉 false
isNumberSafeInt(BigInt(10)); // 👉 false
isNumberSafeInt(Number.MAX_SAFE_INTEGER); // 👉 true
assertNumberSafeInt(Number.MAX_SAFE_INTEGER + 1); // 👉 throws

Array related

ArrayNonEmpty

| Name | Type | Opaque type | Comment | |---------------------|-------------|-----------------|-----------------| | isArrayNonEmpty | unknown[] | ArrayNonEmpty | | | assertArrayNonEmpty | unknown[] | ArrayNonEmpty | |

import { isArrayNonEmpty, assertArrayNonEmpty, type ArrayNonEmpty } from '@httpx/assert';

isArrayNonEmpty([]) // 👉 false
isArrayNonEmpty([0,1]) // 👉 true
isArrayNonEmpty([null]) // 👉 true
assertArrayNonEmpty([]) // 👉 throws

String related

StringNonEmpty

| Name | Type | Opaque type | Comment | |----------------------|-----------|------------------|-----------------| | isStringNonEmpty | string | StringNonEmpty | Trims the value | | assertStringNonEmpty | string | StringNonEmpty | Trims the value |

import { assertStringNonEmpty, isStringNonEmpty, type StringNonEmpty } from '@httpx/assert';

isStringNonEmpty(''); // 👉 false
isStringNonEmpty(' '); // 👉 false: trim by default
assertStringNonEmpty(''); // 👉 throws

ParsableSafeInt

| Name | Type | Opaque type | Comment | |-----------------------|-----------|-------------------|-----------------| | isParsableSafeInt | string | ParsableSafeInt | | | assertParsableSafeInt | string | ParsableSafeInt | |

import { assertParsableSafeInt, isParsableSafeInt } from '@httpx/assert';

isParsableSafeInt(2); // 👉 false
isParsableSafeInt(`${Number.MAX_SAFE_INTEGER}`); // 👉 true
assertParsableSafeInt(`${Number.MAX_SAFE_INTEGER}1`); // 👉 throws

isParsableStrictIsoDateZ

Check if a value is a string that contains an ISO-8601 date time in 'YYYY-MM-DDTHH:mm:ss.sssZ' format (UTC+0 / time). This check allow the value to be safely passed to new Date()or Date.parse() without parser or timezone mis-interpretations. 'T' and 'Z' checks are done in a case-insensitive way.

| Name | Type | Opaque type | Comment | |------------------------------|-----------|--------------------------|-----------------| | isParsableStrictIsoDateZ | string | ParsableStrictIsoDateZ | | | assertParsableStrictIsoDateZ | string | ParsableStrictIsoDateZ | |

import { isParsableStrictIsoDateZ, assertParsableStrictIsoDateZ, type ParsableStrictIsoDateZ } from '@httpx/assert';

isParsableStrictIsoDateZ(new Date().toISOString());   // ✅ true
isParsableStrictIsoDateZ('2023-12-28T23:37:31.653Z'); // ✅ true
isParsableStrictIsoDateZ('2023-12-29T23:37:31.653z'); // ✅ true  (case-insensitive works)
isParsableStrictIsoDateZ('2023-12-28T23:37:31.653');  // ❌ false (missing 'Z')
isParsableStrictIsoDateZ('2023-02-29T23:37:31.653Z'); // ❌ false (No 29th february in 2023)

// assertion
const dateStr = '2023-12-29T23:37:31.653Z';
assertParsableStrictIsoDateZ(dateStr, `Invalid date: ${dateStr}`);

// 👉 assertion passed, safe to use -> ParsableStrictIsoDateZ
const date = new Date(dateStr);
const timestampNumber = Date.parse(dateStr);

assertParsableStrictIsoDateZ('2023-02-29T23:37:31.653Z'); // 💥 throws cause no 29th february

Uuid

isUuid

| Name | Type | Opaque type | Comment | |----------------|-------------------------|--------------------------------------------------|--------| | isUuid | string | UuidV1 \| UuidV3 \| UuidV4 \| UuidV5 \| UuidV7 | | | isUuidV1 | string | UuidV1 | | | isUuidV3 | string | UuidV3 | | | isUuidV4 | string | UuidV4 | | | isUuidV5 | string | UuidV5 | | | isUuidV7 | string | UuidV7 | | | assertUuid | string | UuidV1 \| UuidV3 \| UuidV4 \| UuidV5 \| UuidV7 | | | assertUuidV1 | string | UuidV5 | | | assertUuidV3 | string | UuidV3 | | | assertUuidV4 | string | UuidV4 | | | assertUuidV5 | string | UuidV5 | | | assertUuidV7 | string | UuidV7 | | | getUuidVersion | 1 \| 3 \| 4 \| 5 \| 7 | | |

import { isUuid, isUuidV1, isUuidV3, isUuidV4, isUuidV5 } from "@httpx/assert";
import { assertUuid, assertUuidV1, assertUuidV3, assertUuidV4, assertUuidV5 } from "@httpx/assert";
import { getUuidVersion } from '@httpx/assert';

// Without version
isUuid('90123e1c-7512-523e-bb28-76fab9f2f73d'); // 👉 valid uuid v1, 3, 4 or 5
assertUuid('90123e1c-7512-523e-bb28-76fab9f2f73d');

// With version
assertUuid('90123e1c-7512-523e-bb28-76fab9f2f73d');
assertUuidV5('90123e1c-7512-523e-bb28-76fab9f2f73d')
isUuid('90123e1c-7512-523e-bb28-76fab9f2f73d');
isUuidV4('d9428888-122b-11e1-b85c-61cd3cbb3210'); // 👈 or isUuidV1(''), isUuidV3(''), isUuidV5('')...;

// Utils
getUuidVersion('90123e1c-7512-523e-bb28-76fab9f2f73d'); // 5

Barcode

isEan13

Supported barcodes is currently limited to Ean13

import { isEan13 } from "@httpx/assert";
import { assertEan13 } from "@httpx/assert";

isEan13('1234567890128'); // 👈 will check digit too
assertEan13('1234567890128');

Network

isNetWorkPort

Check whether the value is a valid tcp/udp network port (0-65535)

import { isNetworkPort } from "@httpx/assert";
import { assertNetworkPort } from "@httpx/assert";
import { type NetworkPort } from "@httpx/assert";

isNetworkPort(443); // 👈 weak opaque type is NetworkPort
assertNetworkPort(443);

Http

isHttpMethod

Check whether the value is a specific http method (case-insensitive).

import { isHttpMethod } from "@httpx/assert";
import { assertHttpMethod } from "@httpx/assert";
import { type HttpMethod } from "@httpx/assert";

const value: unknown = 'GET';

isHttpMethod('GET', value); // 👈 weak opaque type is HttpMethod
assertHttpMethod('GET', value);

isValidHttpMethod

Check whether the value is a valid http method (case-insensitive).

import { isHttpValidMethod } from "@httpx/assert";
import { assertHttpValidMethod } from "@httpx/assert";
import { type HttpMethod } from "@httpx/assert";

const value: unknown = 'GET';

isHttpValidMethod(value); // 👈 weak opaque type is HttpMethod
assertHttpValidMethod(value);

Bundle size

Code and bundler have been tuned to target a minimal compressed footprint for the browser.

ESM individual imports are tracked by a size-limit configuration.

| Scenario | Size (compressed) | |----------------------------------------|------------------:| | Import isPlainObject | ~ 100b | | Import isUuid | ~ 175b | | Import isEan13 | ~ 117b | | All typeguards, assertions and helpers | ~ 1700b |

For CJS usage (not recommended) track the size on bundlephobia.

Compatibility

| Level | CI | Description | |--------------|----|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| Node | ✅ | CI for 18.x, 20.x & 22.x. | | Browser | ✅ | Tested with latest chrome (vitest/playwright) | | Browserslist | ✅ | > 95% on 12/2023. Mins to Chrome 96+, Firefox 90+, Edge 19+, iOS 12+, Safari 12+, Opera 77+ | | Edge | ✅ | Ensured on CI with @vercel/edge-runtime. | | Cloudflare | ✅ | Ensured with @cloudflare/vitest-pool-workers (see wrangler.toml | | Typescript | ✅ | TS 5.0+ / are-the-type-wrong checks on CI. |
| ES2022 | ✅ | Dist files checked with es-check |

For older browsers: most frontend frameworks can transpile the library (ie: nextjs...)

Acknowledgments

Special thanks for inspiration:

• sindresorhus/is
• webmozarts/assert

Contributors

Contributions are warmly appreciated. Have a look to the CONTRIBUTING document.

Sponsors

If my OSS work brightens your day, let's take it to new heights together! Sponsor, coffee, or star – any gesture of support fuels my passion to improve. Thanks for being awesome! 🙏❤️

Special thanks to

License

MIT © belgattitude and contributors.