api/query/view/ngrams_last_token_only.js

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

/**
  Ngrams view which trims the 'input:name' and only uses the LAST TOKEN.

  eg. if the input was "100 foo str", then 'input:name' would only be 'str'
  note: it is assumed that the rest of the input is matched using another view.

  code notes: this view makes a copy of the $vs object in order to change their
  values without mutating the original values, which may be expected in their
  unaltered form by other views.
**/

module.exports = function( vs ){

  // get a copy of the *tokens_incomplete* tokens produced from the input:name
  var tokens = vs.var('input:name:tokens_incomplete').get();

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

  // make a copy Vars so we don't mutate the original
  var vsCopy = new peliasQuery.Vars( vs.export() );

  // set the 'name' variable in the copy to only the last token
  vsCopy.var('input:name').set( tokens.join(' ') );

  // return the view rendered using the copy
  return {
    'constant_score': {
      'query': ngrams_strict( vsCopy )
    }
  };
};