code: function calculateOccurrences( wordCombinations ) {
  	const occurrences = {};
  
  	forEach( wordCombinations, function( wordCombination ) {
  		const combination = wordCombination.getCombination();
  
  		if ( ! has( occurrences, combination ) ) {
  			occurrences[ combination ] = wordCombination;
  		}
  
  		occurrences[ combination ].incrementOccurrences();
  	} );
  
  	return values( occurrences );
  }
docs: Calculates occurrences for a list of word combinations.
  
  @param {WordCombination[]} wordCombinations The word combinations to calculate occurrences for.
  @returns {WordCombination[]} Word combinations with their respective occurrences.