zoubin

function * permutation (input) {
    let n = input.length
    if (n === 0) {
        yield []
    } else {
        let needle = input.pop()
        for (let p of permutation(input)) {
            for (let i = 0; i < n; i++) {
                let q = p.slice()
                q.splice(i, 0, needle)

zoubin

/**
 * convert `Shared Folders\projects\electron-quick-start`
 * to `Z:\projects\electron-quick-start`
 * See https://github.com/electron/electron/issues/6760
 *
 * Copy the source code to your page
 * or add a script tag with src refering to this module
 * **BEFORE** any module `require` takes place.
 *
 * Now you can `require` modules in HTML script tags as you do in node.

zoubin

// http://jsbin.com/lamakud/edit?html,output
function isValidateDate(datestr) {
  var ms = Date.parse(datestr)
  if (isNaN(ms)) return false
  return ~~(datestr.split(/[^d]/).pop()) === new Date(ms).getDate()
}
module.exports = isValidateDate

zoubin

function isLeap(year) {
  var d = new Date(year + '')
  d.setMonth(1)
  d.setDate(29)
  return d.getDate() === 29
}
module.exports = isLeap