cmpby

Make comparator from key function or less function.

Comparator is a function that given two arguments a and b returns a number that is:

• negative if a precedes b;
• zero if a and b are effectively equal;
• positive if b precedes a.

Comparators are used in such functions as Array.prototype.sort to set up object ordering.

Example

> ['aaa', 'zz', 'd'].sort(cmpby(a => a.length))
[ 'd', 'zz', 'aaa' ]

> ['aaa', 'zz', 'd'].sort(cmpby.less((a, b) => a.length < b.length ))
[ 'd', 'zz', 'aaa' ]

API

cmpby([options], keyfn)

keyfn :: Object -> Key

Constructs comparator from the key function.

cmpby([options], lessfn)

lessfn :: (Object, Object) -> Boolean

Constructs comparator from the less-than function.

cmpby([options])

Returns the default comparator.

options.asc

type | default | description :--: | :-----: | :---------: Boolean | true | If false, inverts comparator

Install

npm install cmpby

License

MIT