import Em from 'ember';
import HrefTo from 'ember-href-to/href-to';

let hrefToClickHandler;
function closestLink(el) {
  if (el.closest) {
    return el.closest('a');
  } else {
    el = el.parentElement;
    while (el && el.tagName !== 'A') {
      el = el.parentElement;
    }
    return el;
  }
}
export default {
  name: 'ember-href-to',
  initialize(applicationInstance) {
    if (hrefToClickHandler !== undefined) {
      document.body.removeEventListener('click', hrefToClickHandler);
    }
    hrefToClickHandler = function _hrefToClickHandler(e) {
      let link = e.target.tagName === 'A' ? e.target : closestLink(e.target);
      if (link) {
        let hrefTo = new HrefTo(applicationInstance, e, link);
        hrefTo.maybeHandle();
      }
    }
    document.body.addEventListener('click', hrefToClickHandler);
  }
};

import Em from 'ember';
import HrefTo from 'ember-href-to/href-to';

let hrefToClickHandler;
function closestLink(el) {
  if (el.closest) {
    return el.closest('a');
  } else {
    el = el.parentElement;
    while (el && el.tagName !== 'A') {
      el = el.parentElement;
    }
    return el;
  }
}
export default {
  name: 'ember-href-to',
  initialize(applicationInstance) {
    document.body.removeEventListener('click', hrefToClickHandler);
    hrefToClickHandler = function(e) {
      let link = e.target.tagName === 'A' ? e.target : closestLink(e.target);
      if (link) {
        let hrefTo = new HrefTo(applicationInstance, e, link);
        hrefTo.maybeHandle();
      }
    }
    document.body.addEventListener('click', hrefToClickHandler);
  }
};

--- 
+++ 
@@ -16,8 +16,10 @@
 export default {
   name: 'ember-href-to',
   initialize(applicationInstance) {
-    document.body.removeEventListener('click', hrefToClickHandler);
-    hrefToClickHandler = function(e) {
+    if (hrefToClickHandler !== undefined) {
+      document.body.removeEventListener('click', hrefToClickHandler);
+    }
+    hrefToClickHandler = function _hrefToClickHandler(e) {
       let link = e.target.tagName === 'A' ? e.target : closestLink(e.target);
       if (link) {
         let hrefTo = new HrefTo(applicationInstance, e, link);
Add a guard to better express the intention

Also added a name to the handler to avoid anonymous function in
stack traces.
