index.js
function isOutside (feature, poly) {
  var a = feature.bbox = feature.bbox || extent(feature)
  var b = poly.bbox = poly.bbox || extent(poly)
  return a[2] < b[0] || a[0] > b[2] || a[3] < b[1] || a[1] > b[3]
}
function isOutside (feature, poly) {
  var a = feature.bbox = feature.bbox || extent(feature)
  var b = poly.bbox = poly.bbox || extent(poly)
  return a[2] < b[0] || a[0] > b[2] || a[3] < b[1] || a[1] > b[3]
}
function isOutside ( feature , poly ) { var a = feature . bbox = feature . bbox || extent ( feature ) var b = poly . bbox = poly . bbox || extent ( poly ) return a [ 2 ] < b [ 0 ] || a [ 0 ] > b [ 2 ] || a [ 3 ] < b [ 1 ] || a [ 1 ] > b [ 3 ] }
no false positives, some false negatives
no false positives some false negatives