morrisonlevi

In EcmaScript 2015 (ES6) the expression (x) => x * 2 means to create an anonymous function with one parameter x that will return x * 2. For example:

(x) => x * 2
// is equivalent to:
function(x) { return x * 2; }

A modified example from [documentation by Mozilla Developer Network][1] page demonstrates how they are useful:

var a = [

"Hydrogen",

arbourd

1. Open Powershell as an administrator
2. Run

   Get-ItemProperty HKLM:\SYSTEM\CurrentControlSet\Enum\HID\*\*\Device` Parameters FlipFlopWheel -EA 0 | ForEach-Object { Set-ItemProperty $_.PSPath FlipFlopWheel 1 }

3. Verify that all mice devices have had their FlipFlopWheel attributes set to 1

   Get-ItemProperty HKLM:\SYSTEM\CurrentControlSet\Enum\HID\*\*\Device` Parameters FlipFlopWheel -EA 0

4. Reboot

manix

function fieldSorterOptimized(fields) {
  var dir = [], i, l = fields.length;
  fields = fields.map(function(o, i) {
    if (o[0] === "-") {
      dir[i] = -1;
      o = o.substring(1);
    } else {
      dir[i] = 1;
    }
    return o;