Create plural diminutives in Dutch

packages/yoastseo/spec/morphology/dutch/addNounSuffixesSpec.js

@@ -65,16 +65,20 @@ describe( "Adds noun suffixes", () => {
 		expect( addNounSuffixes( "baby", morphologyDataNL.addSuffixes, morphologyDataNL.nouns.suffixes ).sort() ).toEqual( [
 			"baby's",
 			"baby'tje",
+			"baby'tjes",
 		].sort() );
 	} );
 	it( "Adds default noun suffixes to a Dutch stem when the correct suffix cannot be predicted", () => {
 		expect( addNounSuffixes( "hond", morphologyDataNL.addSuffixes, morphologyDataNL.nouns.suffixes ).sort() ).toEqual( [
 			"hondje",
+			"hondjes",
 			"hondertje",
+			"hondertjes",
 			"honden",
 			"honders",
 			"hondes",
 			"hondetje",
+			"hondetjes",
 		].sort() );
 	} );
 	it( "Creates a second stem with doubled consonant and adds the right suffixes to each stem", () => {
@@ -83,21 +87,26 @@ describe( "Adds noun suffixes", () => {
 			"ballers",
 			"balles",
 			"balletje",
+			"balletjes",
 		].sort() );
 	} );
 	it( "Creates a second stem with voiced consonant and adds the right suffixes to each stem", () => {
 		expect( addNounSuffixes( "huis", morphologyDataNL.addSuffixes, morphologyDataNL.nouns.suffixes ).sort() ).toEqual( [
 			"huisje",
+			"huisjes",
 			"huisertje",
+			"huisertjes",
 			"huizen",
 			"huizers",
 			"huizes",
 			"huizetje",
+			"huizetjes",
 		].sort() );
 	} );
 	it( "Creates a second stem with an undoubled vowel and adds the right suffixes to each stem", () => {
 		expect( addNounSuffixes( "spoor", morphologyDataNL.addSuffixes, morphologyDataNL.nouns.suffixes ).sort() ).toEqual( [
 			"spoortje",
+			"spoortjes",
 			"sporen",
 			"sporers",
 			"spores",
@@ -111,6 +120,7 @@ describe( "Adds noun suffixes", () => {
 	it( "Replaces -g with -k in stems ending in -ing before attaching the diminutive suffix", () => {
 		expect( addNounSuffixes( "ketting", morphologyDataNL.addSuffixes, morphologyDataNL.nouns.suffixes ).sort() ).toEqual( [
 			"kettinkje",
+			"kettinkjes",
 			"kettingen",
 			"kettingers",
 			"kettinges",

packages/yoastseo/src/morphology/dutch/addNounSuffixes.js

@@ -51,6 +51,22 @@ const getPluralSuffixes = function( stemmedWord, morphologyDataPluralSuffixes )
 	return pluralSuffixes;
 };
 
+/**
+ * Gets the predicted or default diminutive suffixes. Then creates the plural form of all the diminutive suffixes and
+ * returns all the diminutive suffixes.
+ *
+ * @param {string} stemmedWord The stemmed word.
+ * @param {Object} morphologyDataDiminutiveSuffixes The morphology data for adding diminutive suffixes.
+ * @returns {string[]} The diminutive suffixes.
+ */
+const getDiminutiveSuffixes = function( stemmedWord, morphologyDataDiminutiveSuffixes ) {
+	const singularDiminutiveSuffixes = getSuffixes( stemmedWord, morphologyDataDiminutiveSuffixes );
+
+	const pluralDiminutiveSuffixes = singularDiminutiveSuffixes.map( suffix => suffix + "s" );
+
+	return singularDiminutiveSuffixes.concat( pluralDiminutiveSuffixes );
+};
+
 /**
  * Creates additional modified stems if needed and adds the relevant suffixes to the stem(s) in order to create noun forms.
  *
@@ -71,24 +87,24 @@ export function addNounSuffixes( stemmedWord, morphologyDataAddSuffixes, morphol
 	const pluralSuffixes = getPluralSuffixes( stemmedWord, morphologyDataNounSuffixes.pluralSuffixes );
 
 	// Get diminutive suffixes.
-	const diminutiveSuffixes = getSuffixes( stemmedWord, morphologyDataNounSuffixes.diminutiveSuffixes );
+	const diminutiveSuffixes = getDiminutiveSuffixes( stemmedWord, morphologyDataNounSuffixes.diminutiveSuffixes );
 
 	// Join the diminutive and plural suffixes
 	let combinedSuffixes = pluralSuffixes.concat( diminutiveSuffixes );
 
 	const nounForms = [];
 
 	/* If the kje suffix exists in the suffixes for this word,
-	remove the last character of the stem, attach the suffix to the stem, and add the resulting
-	form to the noun forms array. */
+	remove the last character of the stem, add the suffixes -kje and -kjes to the stem, and add the resulting
+	forms to the noun forms array. */
 	if ( combinedSuffixes.includes( "kje" ) ) {
-		combinedSuffixes = combinedSuffixes.filter( suffix => suffix !== "kje" );
-		const kjeForm = stemmedWord.slice( 0, -1 ) + "kje";
-		nounForms.push( kjeForm );
+		const kjeSuffixes = combinedSuffixes.filter( suffix => suffix.includes( "kje" ) );
+		combinedSuffixes = combinedSuffixes.filter( suffix => ! suffix.includes( "kje" ) );
+		nounForms.push( ...applySuffixesToStem( stemmedWord.slice( 0, -1 ), kjeSuffixes ) );
 	}
 
 	// Then find the suffixes that require a stem modification (except for "kje")...
-	const stemModificationSuffixes = [ "en", "ers", "es", "etje" ];
+	const stemModificationSuffixes = morphologyDataNounSuffixes.requireStemModification;
 	const suffixesForModifiedStem = combinedSuffixes.filter( suffix => stemModificationSuffixes.includes( suffix ) );
 
 	// ...and remove them from the suffixesForUnmodifiedStem array;

packages/yoastseo/src/morphology/dutch/generateParticipleForm.js

@@ -101,7 +101,7 @@ const checkInseparablePrefix = function( morphologyDataVerbs, stemmedWord, prefi
 export function generateParticipleForm( morphologyDataVerbs, stemmedWord ) {
 	const inseparableExceptionParticiple = generateInseparableExceptionParticipleForm(
 		stemmedWord,
-		morphologyDataVerbs.inseparableVerbs
+		morphologyDataVerbs.inseparableVerbStems
 	);
 
 	if ( inseparableExceptionParticiple ) {