🙃 Flip-function

Given a function, returns the same function with some parameters reversed. Similar to Haskell's flip, but permits flipping of more than two parameters. Grants flexibility for partial application.

API

Syntax

flip(func[, flipCount[, startIndex]])

Parameters

func

Required. A function, the parameters of which are to be reversed.

flipCount

Optional. A number specifying the number of parameters to reverse. Defaults to 2.

startIndex

Optional. A number specifying the index of the parameter at which to start the reverse. Indexing is zero-based and inclusive. Defaults to 0.

Return

The argument function with some parameters reversed.

Examples

const myFunc = (a, b, c, d) => [a, b, c, d];
 
// only passing function
 
const flipIt = flip(myFunc);
 
flipIt(1, 2, 3, 4) // [ 2, 1, 3, 4 ];
 
// passing flip count
 
const flipItAgain = flip(myFunc, 4);
 
flipItAgain(1, 2, 3, 4) // [ 4, 3, 2, 1 ];
 
// passing flip count and start index
 
const flipItOnceMore = flip(myFunc, 2, 2);
 
flipItOnceMore(1, 2, 3, 4) // [ 1, 2, 4, 3];

Test

Tested with AVA.

npm test

or

npx ava