NOTE: The package what-is was renamed to wots. Please, consider installing the renamed version.
why?
The library was written as a simple coding exercise, but then appeared useful to share 😉
how?
npm install --save what-is
and then
var whatis = ; // ... if === 'NaN' // do some stuffwhat?
whatis() function returns reasonable type names for tested values:
| description | input | result |
|---|---|---|
| null | null |
'null' |
| undefined | undefined |
'undefined' |
| strings | 'foo' |
'string' |
'' |
'string' |
|
['Hello', 'world!'].join(' ') |
'string' |
|
new String() |
'string' |
|
| numbers | 5 |
'number' |
parseInt(42) |
'number' |
|
new Number('3') |
'number' |
|
NaN |
'NaN' |
|
Infinity |
'Infinity' |
|
1 / -0 |
'Infinity' |
|
| boolean values | false |
'boolean' |
!!nonEmptyVariable |
'boolean' |
|
new Boolean('0') |
'boolean' |
|
| regular expressions | /^test$/g |
'regexp' |
new RegExp('needle', 'i') |
'regexp' |
|
| arrays | ['foo', 'bar', 'baz'] |
'array' |
new Array(10) |
'array' |
|
| objects | { foo: 'bar'} |
'object' |
{} |
'object' |
|
new Object() |
'object' |
|
Object.create(null) |
throws error (to be fixed) | |
| functions | function () {} |
'function' |
new Function('return null') |
'function' |
|
| date objects | new Date() |
'date' |
| errors | new Error('error!') |
'error' |
new TypeError('type error!') |
'error' |
|
| arguments objects | (function(){return arguments;})() |
'arguments' |
| class constructors | new MyClass() |
'myclass' |
new Buffer() |
'buffer' |
|
new XMLHttpRequest() |
'xmlhttprequest' |
|
| promises | new Promise(function() {}) |
'promise' |
Promise.resolve('data') |
'promise' |
|
Promise.reject(new Error('Oop!')) |
'promise' |
Note: for more examples see test file