reliable-type

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)
~~~

| 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" |
| 1_000_000n | [BigInt] | "BigInt" |
| [-]Infinity | Infinity | "Infinity" |
| [NaN] | NaN | "NaN" |
| [Math] | Math | "Math" |
| Symbol("*") | [Symbol] | "Symbol" |
| new Intl.Segmenter() | [Segmenter] | "Segmenter" |
| new Date() | Date | "Date" |
| /./g/new RegExp(".") | RegExp | "RegExp" |
| new URL("https://github.com") | URL | "URL" |
| const buffer = Buffer.from("data") | [Buffer] | "Buffer" |
| fs.createReadStream(buffer) | [ReadStream] | "ReadStream" |
| fs.createWriteStream("/dev/null") | [WriteStream] | "WriteStream" |
| new Uint8Array([0, 255]) | [Uint8Array] | "Uint8Array" |
| [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" |

$3

~~~ 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
[Segmenter]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Intl/Segmenter

[Buffer]: https://nodejs.org/api/buffer.html
[ReadStream]: https://nodejs.org/api/fs.html#class-fsreadstream
[WriteStream]: https://nodejs.org/api/fs.html#class-fswritestream
[Uint8Array]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array
[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