https://github.com/danielbayley/reliable-type
Reliable runtime type information.
https://github.com/danielbayley/reliable-type
npm npm-module npm-package npmjs runtime runtime-typechecking runtime-types runtime-validation type typechecker types typescript
Last synced: 5 days ago
JSON representation
Reliable runtime type information.
- Host: GitHub
- URL: https://github.com/danielbayley/reliable-type
- Owner: danielbayley
- License: mit
- Created: 2024-07-11T23:35:15.000Z (almost 2 years ago)
- Default Branch: main
- Last Pushed: 2026-05-01T14:43:36.000Z (22 days ago)
- Last Synced: 2026-05-01T15:10:23.999Z (22 days ago)
- Topics: npm, npm-module, npm-package, npmjs, runtime, runtime-typechecking, runtime-types, runtime-validation, type, typechecker, types, typescript
- Language: JavaScript
- Homepage: https://npm.im/reliable-type
- Size: 41 KB
- Stars: 1
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE.md
Awesome Lists containing this project
README
Reliable [Type]
===============
Reliable runtime [type] information.
## Install
~~~ sh
pnpm install reliable-type
~~~
Example
-------
The provided `type` method is more reliable than some combination of [`typeof`]
and [`instanceof`]. While the [`.constructor`] `Object` property is strong
—and recommended, in absence of a dependency like this—it can technically be
reassigned. It will always `return` the correct type as an informative,
specific Type or [`tag`] `String`. Extra [type]s are also available to `import`:
~~~ js
import assert from "node:assert/strict"
import { type, types, tag, tags } from "reliable-type"
import { GeneratorFunction } from "reliable-type/types"
function* generator() { yield * [1, 2, 3] }
const Type = type(generator)
const Tag = tag(generator)
assert.equal(Type, GeneratorFunction)
assert.equal(Tag, "GeneratorFunction")
assert.equal(Type, types.GeneratorFunction)
assert.equal(Tag, tags.GeneratorFunction)
~~~
[Type]s
---------------------------------------------------------------------------------------------------------
| Expression | [`type`][type] | [`tag`] |
|:--------------------------------------------|:---------------------------|:---------------------------|
| `undefined` | `undefined` | `"undefined"` |
| `null` | `null` | `"null"` |
| `true`/`false` | `Boolean` | `"Boolean"` |
| `"string"` | `String` | `"String"` |
| `-0`/`1_000`/`0.1` | [`Number`] | `"Number"` |
| [`0xAf`]/[`0o1`]/[`0b1`] | `Number` | `"Number"` |
| [`3.1415e+1`]/[`Math.PI`][`Math`] | `Number` | `"Number"` |
| `2n^63n` | [`BigInt`] | `"BigInt"` |
| [`-`]`Infinity` | `Infinity` | `"Infinity"` |
| [`NaN`] | `NaN` | `"NaN"` |
| [`Math`] | `Math` | `"Math"` |
| `Symbol("*")` | [`Symbol`] | `"Symbol"` |
| `/.*/g`/`new RegExp(".*")` | `RegExp` | `"RegExp"` |
| `new Error("message")` | [`Error`] | `"Error"` |
| `new EvalError("message")` | [`EvalError`] | `"EvalError"` |
| `new RangeError("message")` | [`RangeError`] | `"RangeError"` |
| `new ReferenceError("message")` | [`ReferenceError`] | `"ReferenceError"` |
| `new SyntaxError("message")` | [`SyntaxError`] | `"SyntaxError"` |
| `new TypeError("message")` | [`TypeError`] | `"TypeError"` |
| `new URIError("message")` | [`URIError`] | `"URIError"` |
| `new AggregateError("message")` | [`AggregateError`] | `"AggregateError"` |
| `new Intl.Segmenter()` | [`Segmenter`] | `"Segmenter"` |
| `new Date()` | [`Date`] | `"Date"` |
| `new URL("https://github.com")` | `URL` | `"URL"` |
| `fs.createReadStream(buffer)` | [`ReadStream`] | `"ReadStream"` |
| `fs.createWriteStream("/dev/null")` | [`WriteStream`] | `"WriteStream"` |
| `const buffer = Buffer.from("data")` | [`Buffer`] | `"Buffer"` |
| `new ArrayBuffer(1024)` | [`ArrayBuffer`] | `"ArrayBuffer"` |
| `new Int8Array([-128, 127]) | [`Int8Array`] | `"Int8Array"` |
| `new Uint8Array([0, 255])` | [`Uint8Array`] | `"Uint8Array"` |
| `new new Uint8ClampedArray([0, 255])` | [`Uint8ClampedArray`] | `"Uint8ClampedArray"` |
| `new Int16Array([-32768, 32767])` | [`Int16Array`] | `"Int16Array"` |
| `new Uint16Array([0, 65535])` | [`Uint16Array`] | `"Uint16Array"` |
| `new Int32Array([-2147483648, 2147483647])` | [`Int32Array`] | `"Int32Array"` |
| `new Uint32Array([0, 4294967295])` | [`Uint32Array`] | `"Uint32Array"` |
| `new Float32Array([-3.4e38, 3.4e38])` | [`Float32Array`] | `"Float32Array"` |
| `new Float64Array([-1.8e308, 1.8e308])` | [`Float64Array`] | `"Float64Array"` |
| `new BigInt64Array([-2n^63n, 2n^63n])` | [`BigInt64Array`] | `"BigInt64Array"` |
| `new BigUint64Array([0n, 2n^63n])` | [`BigUint64Array`] | `"BigUint64Array"` |
| `[1 ,2 ,3]`/`Array.from("abc")` | `Array` | `"Array"` |
| `new Set([1, 2, 3])` | [`Set`] | `"Set"` |
| `new WeakSet()` | [`WeakSet`] | `"WeakSet"` |
| `new WeakMap()` | [`WeakMap`] | `"WeakMap"` |
| `const map = new Map().set("a", 1)` | [`Map`] | `"Map"` |
| `map.entries()` | [`Iterator`] | `"Iterator"` |
| `const object = { a: 1, b: 2 }` | `Object` | `"Object"` |
| `new Proxy(object, {})` | [`Proxy`] | `"Proxy"` |
| `Proxy.revocable(object, {})` | `Proxy` | `"Proxy"` |
| `{ [Symbol.toStringTag]: "tag" }` | `"tag"` | [`"tag"`][`tag`] |
| [`JSON`] | `JSON` | `"JSON"` |
| `function() { return arguments }(1, 2)` | [`Arguments`] | `"Arguments"` |
| `[].reduce`/`() => {}` | `Function` | `"Function"` |
| `async () => Promise.resolve(true)` | [`AsyncFunction`] | `"AsyncFunction"` |
| `Promise.resolve(true)` | [`Promise`] | `"Promise"` |
| `function* generator() { yield * [1, 2] }` | [`GeneratorFunction`] | `"GeneratorFunction"` |
| `generator()` | [`Generator`] | `"Generator"` |
| `async function* gen() { yield * [1, 2] }` | [`AsyncGeneratorFunction`] | `"AsyncGeneratorFunction"` |
| `gen()` | [`AsyncGenerator`] | `"AsyncGenerator"` |
| `new (class Class {})()` | `Class` | [`"Class"`] |
| `new (class Extended extends Class {})()` | `ExtendedClass` | [`"ExtendedClass"`] |
| `fs.opendir(dir)` | [`Dir`] | `"Dir"` |
| `fs.readdir(dir, { withFileTypes: true })` | [`Dirent`] | `"Dirent"` |
### Aliases
~~~ js
import { typeOf, toStringTag } from "reliable-type"
~~~
License
-------
[MIT] © [Daniel Bayley]
[MIT]: LICENSE.md
[Daniel Bayley]: https://github.com/danielbayley
[type]: https://developer.mozilla.org/docs/Web/JavaScript/Guide/Grammar_and_types#data_types
[`typeof`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Operators/typeof
[`instanceof`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Operators/instanceof
[`.constructor`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object/constructor
[`Number`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number
[`0xAf`]: https://developer.mozilla.org/docs/Web/JavaScript/Guide/Numbers_and_dates#hexadecimal_numbers
[`0o1`]: https://developer.mozilla.org/docs/Web/JavaScript/Guide/Numbers_and_dates#octal_numbers
[`0b1`]: https://developer.mozilla.org/docs/Web/JavaScript/Guide/Numbers_and_dates#binary_numbers
[`3.1415e+1`]: https://developer.mozilla.org/docs/Web/JavaScript/Guide/Numbers_and_dates#exponentiation
[`BigInt`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/BigInt
[`NaN`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/NaN
[`Math`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Math
[`Symbol`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Symbol
[`tag`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Symbol/toStringTag
[`JSON`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/JSON
[`Error`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error
[`EvalError`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/EvalError
[`RangeError`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/RangeError
[`ReferenceError`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/ReferenceError
[`SyntaxError`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/SyntaxError
[`TypeError`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/TypeError
[`URIError`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/URIError
[`AggregateError`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/AggregateError
[`Segmenter`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Intl/Segmenter
[`Date`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Date
[`ReadStream`]: https://nodejs.org/api/fs.html#class-fsreadstream
[`WriteStream`]: https://nodejs.org/api/fs.html#class-fswritestream
[`Buffer`]: https://nodejs.org/api/buffer.html
[`ArrayBuffer`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer
[`Int8Array`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Int8Array
[`Uint8Array`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array
[`Uint8ClampedArray`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Uint8ClampedArray
[`Int16Array`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Int16Array
[`Uint16Array`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Uint16Array
[`Int32Array`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Int32Array
[`Uint32Array`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Uint32Array
[`Float32Array`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Float32Array
[`Float64Array`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Float64Array
[`BigInt64Array`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/BigInt64Array
[`BigUint64Array`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/BigUint64Array
[`Set`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Set
[`WeakSet`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/WeakSet
[`WeakMap`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/WeakMap
[`Map`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Map
[`Iterator`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Iterator
[`Proxy`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Proxy
[`Arguments`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Functions/arguments
[`AsyncFunction`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Statements/async_function
[`Promise`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Promise
[`GeneratorFunction`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Statements/function*
[`Generator`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Generator
[`AsyncGeneratorFunction`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/AsyncGeneratorFunction
[`AsyncGenerator`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/AsyncGenerator
[`"Class"`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Classes
[`"ExtendedClass"`]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Classes/extends
[`Dir`]: https://nodejs.org/api/fs.html#class-fsdir
[`Dirent`]: https://nodejs.org/api/fs.html#class-fsdirent