feat(multi_match): Remove old multi_match view

BREAKING CHANGE: the old multi_match view is removed.

I don't remember writing it, but since
#14 in early 2016(!) we have had a
general purpose view for
[multi_match](https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-multi-match-query.html)
queries.

This view doesn't fit our current pattern for keeping general purpose
(i.e. corresponding to built in Elasticsearch query) views in the
`view/leaf` directory, and it doesn't support as much functionality as
the `multi_match` view @Joxit made for us in
#114 last year.

This PR removes the older view, and in the process converts the
`admin_multi_match` view over to using the new `multi_match` leaf query.

While I don't think anything in the Pelias API uses the old
`multi_match` query directly, this removal will require changes to the
API tests because of minor differences in the final output.

index.js

@@ -28,7 +28,6 @@ module.exports.view = {
   address: require('./view/address'),
   admin: require('./view/admin'),
   admin_multi_match: require('./view/admin_multi_match'),
-  multi_match: require('./view/multi_match'),
   categories: require('./view/categories'),
   boundary_circle: require('./view/boundary_circle'),
   boundary_rect: require('./view/boundary_rect'),

test/run.js

@@ -24,7 +24,6 @@ var tests = [
   require('./view/focus.js'),
   require('./view/focus_only_function.js'),
   require('./view/layers.js'),
-  require('./view/multi_match.js'),
   require('./view/ngrams.js'),
   require('./view/phrase.js'),
   require('./view/popularity.js'),

test/view/admin_multi_match.js

@@ -80,13 +80,15 @@ module.exports.tests.no_exceptions_conditions = function(test, common) {
     vs.var('input:property2', 'property2 value');
     vs.var('admin:property2:field', 'property2_field value');
     vs.var('admin:property2:boost', 'property2_boost value');
+    vs.var('multi_match:type', 'cross_fields');
 
     var admin_multi_match = require('../../view/admin_multi_match')(['property1', 'property2'], 'analyzer value');
 
     var actual = admin_multi_match(vs);
 
     var expected = {
       'multi_match': {
+        'type': 'cross_fields',
         'fields': [
           'property1_field value^property1_boost value',
           'property2_field value^property2_boost value'
@@ -101,10 +103,11 @@ module.exports.tests.no_exceptions_conditions = function(test, common) {
 
   });
 
-  test('boosts should default to 1 when not specified', function(t) {
+  test('boosts should default to unset when not specified', function(t) {
     var vs = new VariableStore();
     vs.var('input:property1', 'property1 value');
     vs.var('admin:property1:field', 'property1_field value');
+    vs.var('multi_match:type', 'cross_fields');
     // there is no boost
 
     var admin_multi_match = require('../../view/admin_multi_match')(['property1'], 'analyzer value');
@@ -113,8 +116,9 @@ module.exports.tests.no_exceptions_conditions = function(test, common) {
 
     var expected = {
       'multi_match': {
+        'type': 'cross_fields',
         'fields': [
-          'property1_field value^1'
+          'property1_field value'
         ],
         'query': { $: 'property1 value' },
         'analyzer': 'analyzer value'

view/admin_multi_match.js

@@ -2,7 +2,7 @@
   this view is wrapped in a function so it can be re-used
 **/
 
-var multi_match = require('./multi_match');
+var multi_match = require('../lib/leaf/multi_match');
 
 /*
  * Match several admin fields against the same query
@@ -22,18 +22,13 @@ module.exports = function( admin_properties, analyzer ){
       return null;
     }
 
-    // from the input parameters, generate a list of fields with boosts to
-    // query against
-    var fields_with_boosts = valid_admin_properties.map(function(admin_property) {
-      var boost = 1;
-      if (vs.isset('admin:' + admin_property + ':boost')) {
-        boost = vs.var('admin:' + admin_property + ':boost');
+    const fields = valid_admin_properties.map(function(admin_property) {
+      if (vs.isset(`admin:${admin_property}:boost`)) {
+        return vs.var(`admin:${admin_property}:field`) + '^' +
+          vs.var(`admin:${admin_property}:boost`);
+      } else {
+        return vs.var(`admin:${admin_property}:field`).get();
       }
-
-      return {
-        field: vs.var('admin:' + admin_property + ':field'),
-        boost: boost
-      };
     });
 
     // the actual query text is simply taken from the first valid admin field
@@ -42,7 +37,7 @@ module.exports = function( admin_properties, analyzer ){
     var queryVar = 'input:' + valid_admin_properties[0];
 
     // send the parameters to the standard multi_match view
-    var view = multi_match(vs, fields_with_boosts, analyzer, queryVar);
+    var view = multi_match(vs.var('multi_match:type').get(), fields, vs.var(queryVar), { analyzer: analyzer });
 
     return view;
   };