feat(libpostal_patch): refactor diagonals patch to use an index and lodash functions

controller/libpostal.js

@@ -136,19 +136,24 @@ function patchBuggyResponses(response){
     });
   }
 
+  // generate an index to avoid multiple iterations over the response array
+  let idx = {};
+  response.forEach((res, pos) => idx[res.label] = _.assign({ _pos: pos }, res));
+
   // known bug where the street name is only a directional, in this case we will merge it
   // with the subsequent element.
   // note: the bug only affects diagonals, not N,S,E,W
   // https://github.com/OpenTransitTools/trimet-mod-pelias/issues/20#issuecomment-417732128
-  for( var i=0; i<response.length-1; i++ ){ // dont bother checking the last element
-    if( 'road' !== response[i].label ){ continue; }
-    if( 'string' !== typeof response[i].value ){ continue; }
-    if( 2 !== response[i].value.length ){ continue; }
-    if( DIAGONAL_DIRECTIONALS.includes( response[i].value.toLowerCase() ) ){
-      if( 'string' !== typeof response[i+1].value ){ continue; }
-      response[i].value += ' ' + response[i+1].value; // merge elements
-      response.splice(i+1, 1); // remove merged element
-      break;
+  if( response.length > 1 ){
+    let road = _.get(idx, 'road');
+    if( _.isPlainObject(road) && _.isString(road.value) && road.value.length === 2 ){
+      if( DIAGONAL_DIRECTIONALS.includes( road.value.toLowerCase() ) ){
+        let subsequentElement = response[road._pos+1];
+        if( _.isString(subsequentElement.value) ){
+          response[road._pos].value += ' ' + subsequentElement.value; // merge elements
+          response.splice(road._pos+1, 1); // remove merged element
+        }
+      }
     }
   }