feat(popularity_bands): add post/popularity.js script

Document.js

@@ -45,6 +45,7 @@ function Document( source, layer, source_id ){
   this.addPostProcessingScript( require('./post/seperable_street_names').post );
   this.addPostProcessingScript( require('./post/deduplication') );
   this.addPostProcessingScript( require('./post/language_field_trimming') );
+  this.addPostProcessingScript( require('./post/popularity') );
 
   // mandatory properties
   this.setSource( source );

post/popularity.js

@@ -0,0 +1,33 @@
+/**
+ * Minimum popularity post-processing script ensures that every document
+ * meets a minimum popularity value based on the layer to which it belongs.
+ *
+ * For more info see:
+ * - https://github.com/pelias/openstreetmap/pull/493#issuecomment-503019975
+ * - https://github.com/pelias/openstreetmap/blob/master/stream/popularity_mapper.js
+ */
+
+const _ = require('lodash');
+
+const MIN_POPULARITY_MAP = {
+  postalcode: 9000
+};
+
+function popularity(doc) {
+  let minValue = _.get(MIN_POPULARITY_MAP, doc.getLayer());
+
+  // only apply to layers listed in the mapping above
+  if (!_.isFinite(minValue)) { return; }
+
+  // avoid setting a popularity of 0 (or less)
+  if (minValue <= 0) { return; }
+
+  // skip updating records where the current popularity exceeds the minimum
+  let currentValue = doc.getPopularity();
+  if (_.isFinite(currentValue) && currentValue >= minValue) { return; }
+
+  // set the minimum popularity for this layer
+  doc.setPopularity(minValue);
+}
+
+module.exports = popularity;

test/document/post.js

@@ -4,7 +4,8 @@ const intersections = require('../../post/intersections');
 const seperable_street_names = require('../../post/seperable_street_names').post;
 const deduplication = require('../../post/deduplication');
 const language_field_trimming = require('../../post/language_field_trimming');
-const DEFAULT_SCRIPTS = [intersections, seperable_street_names, deduplication, language_field_trimming ];
+const popularity = require('../../post/popularity');
+const DEFAULT_SCRIPTS = [intersections, seperable_street_names, deduplication, language_field_trimming, popularity];
 
 module.exports.tests = {};
 

test/post/popularity.js

@@ -0,0 +1,66 @@
+const Document = require('../../Document');
+const popularity = require('../../post/popularity');
+
+module.exports.tests = {};
+
+const MIN_POSTCODE_POPULARITY = 9000;
+module.exports.tests.postalcode = function (test) {
+  test('postalcode - empty', function (t) {
+    var doc = new Document('mysource', 'postalcode', 'myid');
+
+    popularity(doc);
+    t.deepEquals(doc.getPopularity(), MIN_POSTCODE_POPULARITY);
+
+    t.end();
+  });
+  test('postalcode - zero', function (t) {
+    var doc = new Document('mysource', 'postalcode', 'myid');
+    doc.setPopularity(0);
+
+    popularity(doc);
+    t.deepEquals(doc.getPopularity(), MIN_POSTCODE_POPULARITY);
+
+    t.end();
+  });
+  test('postalcode - above minimum', function (t) {
+    var doc = new Document('mysource', 'postalcode', 'myid');
+    doc.setPopularity(9999999);
+
+    popularity(doc);
+    t.deepEquals(doc.getPopularity(), 9999999);
+
+    t.end();
+  });
+  test('postalcode - below minimum', function (t) {
+    var doc = new Document('mysource', 'postalcode', 'myid');
+    doc.setPopularity(100);
+
+    popularity(doc);
+    t.deepEquals(doc.getPopularity(), MIN_POSTCODE_POPULARITY);
+
+    t.end();
+  });
+};
+
+// layers not listed in MIN_POPULARITY_MAP should result in a no-op
+module.exports.tests.noop = function (test) {
+  test('other layers - no-op', function (t) {
+    var doc = new Document('mysource', 'mylayer', 'myid');
+
+    popularity(doc);
+    t.deepEquals(doc.getPopularity(), undefined);
+
+    t.end();
+  });
+};
+
+module.exports.all = function (tape, common) {
+
+  function test(name, testFunction) {
+    return tape('post/popularity: ' + name, testFunction);
+  }
+
+  for (var testCase in module.exports.tests) {
+    module.exports.tests[testCase](test, common);
+  }
+};

test/run.js

@@ -26,6 +26,7 @@ var tests = [
   require('./post/deduplication.js'),
   require('./post/seperable_street_names.js'),
   require('./post/language_field_trimming.js'),
+  require('./post/popularity.js'),
   require('./DocumentMapperStream.js'),
   require('./util/transform.js'),
   require('./util/valid.js'),