moy-fp/src/Function/empty.js

A functional programming library.

import curry from './curry'
import is from '../Type/is'

/**
 * a -> a | undefined
 */
const empty = curry(
  (x) => {
    if(x.empty){
      return x.empty()
    }
    switch(is(x)){
      case 'String': return '';
      case 'Array': return [];
      case 'Object': return {};
      default: undefined;
    }
  }
)

export default empty