feat(libpostal_patch): add a libpostal patch which allows recasting labels

controller/libpostal.js

@@ -114,12 +114,29 @@ function setup(libpostalService, should_execute) {
   return controller;
 }
 
+const RECAST_LABELS = [{ value: 'zoo', label: { to: 'house' } }];
 const DIAGONAL_DIRECTIONALS = ['ne','nw','se','sw'];
 
 // apply fixes for known bugs in libpostal
 function patchBuggyResponses(response){
   if( !Array.isArray(response) || !response.length ){ return response; }
 
+  // recast labels for certain values, currently only applied to parses which return a single label.
+  // the RECAST_LABELS array contains match/replace conditions which are applied in order.
+  // the 'value' and 'label.to' properties are mandatory, they define the value to match on and
+  // the replacement label to assign. you may optionally also provide 'label.from' which will restrict
+  // replacements to only records with BOTH a matching 'value' and a matching 'label.from'.
+  if( response.length === 1 ){
+    let first = response[0];
+    for( var ii=0; ii<RECAST_LABELS.length; ii++ ){
+      let recast = RECAST_LABELS[ii];
+      if( !recast.hasOwnProperty('label') || !recast.label.hasOwnProperty('to') ){ continue; }
+      if( recast.value !== first.value ){ continue; }
+      if( recast.label.hasOwnProperty('from') && recast.label.from !== first.label ){ continue; }
+      response[0].label = recast.label.to;
+    }
+  }
+
   // 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

test/unit/controller/libpostal.js

@@ -357,6 +357,45 @@ module.exports.tests.bug_fixes = (test, common) => {
 
   });
 
+  test('bug fix: recast label for "zoo" from borough/city_district to house', t => {
+    const service = (req, callback) => {
+      const response =[
+        {
+          'label': 'city_district',
+          'value': 'zoo'
+        }
+      ];
+
+      callback(null, response);
+    };
+
+    const controller = libpostal(service, () => true);
+
+    const req = {
+      clean: {
+        text: 'original query'
+      },
+      errors: []
+    };
+
+    controller(req, undefined, () => {
+      t.deepEquals(req, {
+        clean: {
+          text: 'original query',
+          parser: 'libpostal',
+          parsed_text: {
+            query: 'zoo'
+          }
+        },
+        errors: []
+      }, 'req should not have been modified');
+
+      t.end();
+
+    });
+
+  });
+
 };
 
 module.exports.all = (tape, common) => {