typeofAnything

A little ES20xx module to determine the type of ... well, anything one throws at it.

The code is available as an ESM module, as a browser script and as a browser script containing a factory function.

The module is also available from NPM.

Exports

The module exports:

• default: a function to determine the type of a given input. Syntax:

  [imported default function](input, [...type] | {...})

  Note: for the {...} parameter, see the demonstration page

• $Wrap: a function that wraps input and returns an Object with keys:

  • value: the input value (can also be undefined, null, NaN or Infinity)
  • is([...types]|{...}): function to determine the type of the wrapped input. This may also be [Symbol.is].
  • type: returns (a string representation) of the type of the wrapped input. This may also be [Symbol.type]

• maybe: a utility function that returns either a tested value, or an error value of choice, syntax

  maybe({trial: [function][, whenError: function]}

  Note: without a whenError parameter, maybe returns undefined when trial fails.

• isNothing(input:any[, all: boolean]: a function to check if input is either null || undefined (all: false) or null || undefined || NaN || Infinity (all: true).

• xProxy: in the typeofAnything module the native Proxy constructor is rewritten, which enables checking if input is a proxy instance (and its constituting type). xProxy is an Object to enable/disable this. Syntax:

  • xProxy.native(): use the native ES20xx Proxy constructor (disable type checking for proxies - so opt out from module default)
  • xProxy.custom(): use the custom Proxy constructor (enable type checking for proxies)

For an extensive set of examples see the demonstration page or fiddle with it with a fork of this Stackblitz project.

Import the module

Your script should be of type module.

<script type="module">
  import IS from "[path to]/typeofany.module.js";
  // or 
  const IS = (await import("[path to]/typeofany.module.js")).default;
</script>

Use in browser

Create a script tag in your html:

<script src="[path to]/typeofany.browser.js")</script>

Subsequently in your script (for example)

<script>
  const isObject = IS({}, Array, Object);
  const nothing = null;
  const isNothingNull = nothing?.[is](null) || $Wrap(nothing).is(null); 
  /* ... */
</script>

Use in browser with factory

Create a script tag in your html:

<script src="[path to]/typeofany.browser-factory.js")</script>

Subsequently in your script (for example)

<script>
  const {IS, $Wrap} = TOAFactory();
  const isObject = IS({}, Array, Object);
  const nothing = null;
  const isNothingNull = nothing?.is(null) || $Wrap(nothing).is(null);
  
  /* ... */
</script>