Use var for compatibility

index.js

@@ -1,20 +1,20 @@
-const sha3 = require('js-sha3').keccak_256
-const uts46 = require('idna-uts46')
+var sha3 = require('js-sha3').keccak_256
+var uts46 = require('idna-uts46')
 
 module.exports = function namehash (inputName) {
   // Reject empty names:
-  let node = ''
-  for (let i = 0; i < 32; i++) {
+  var node = ''
+  for (var i = 0; i < 32; i++) {
     node += '00'
   }
 
   name = normalize(inputName)
 
   if (name) {
-    const labels = name.split('.')
+    var labels = name.split('.')
 
     for(var i = labels.length - 1; i >= 0; i--) {
-      const labelSha = sha3(labels[i])
+      var labelSha = sha3(labels[i])
       node = sha3(new Buffer(node + labelSha, 'hex'))
     }
   }