api/query/view/boost_exact_matches.js

var peliasQuery = require('pelias-query'),
    searchDefaults = require('../search_defaults');

/**
  This view (unfortunately) requires autocomplete to use the phrase.* index.

  ideally we wouldn't need to use this, but at time of writing we are unable
  to distinguish between 'complete tokens' and 'grams' in the name.* index.

  this view was introduced in order to score exact matches higher than partial
  matches, without it we find results such as "Clayton Avenue" appearing first
  in the results list for the query "Clay Av".

  the view uses some of the values from the 'search_defaults.js' file to add an
  additional 'SHOULD' condition which scores exact matches slighly higher
  than partial matches.
**/

module.exports = function( vs ){

  // make a copy of the variables so we don't interfere with the values
  // passed to other views.
  var vsCopy = new peliasQuery.Vars( vs.export() );

  // copy phrase:* values from search defaults
  vsCopy.var('phrase:analyzer').set(searchDefaults['phrase:analyzer']);
  vsCopy.var('phrase:field').set(searchDefaults['phrase:field']);

  // split the 'input:name' on whitespace
  var name = vs.var('input:name').get(),
      tokens = name.split(' ');

  // if the query is incomplete then we need to remove
  // the final (incomplete) token as it will not match
  // tokens in the phrase.* index.
  if( !vs.var('input:name:isComplete').get() ){
    tokens.pop();
  }

  // no valid tokens to use, fail now, don't render this view.
  if( tokens.length < 1 ){ return null; }

  // set 'input:name' to be only the fully completed characters
  vsCopy.var('input:name').set( tokens.join(' ') );

  return peliasQuery.view.phrase( vsCopy );
};