Merge pull request #101 from reload/related-materials-exclude-empty-p…

…rops

Exclude clauses with empty data when searching for related materials

src/apps/related-materials/related-materials.entry.jsx

@@ -175,18 +175,36 @@ function RelatedMaterialsEntry({
   maxTries
 }) {
   const coverClient = new CoverService({ baseUrl: coverServiceUrl });
-  const subject = `term.subject any "${subjects}"`;
-  const category = `term.category any "${categories}"`;
-  const source = `term.acSource any "${sources}"`;
-  const excludeTitle = `phrase.title="${rawExcludeTitle}"`;
-  const query = `${subject} and ${category} and ${source} not ${excludeTitle}`;
+
+  // We may be passed empty strings which will lead to an invalid query.
+  // Compile query clauses using only arguments with actual values.
+  const includes = [];
+  if (subjects) {
+    includes.push(`term.subject any "${subjects}"`);
+  }
+  if (categories) {
+    includes.push(`term.category any "${categories}"`);
+  }
+  if (sources) {
+    includes.push(`term.acSource any "${sources}"`);
+  }
+  const excludes = [];
+  if (rawExcludeTitle) {
+    excludes.push(`not phrase.title="${rawExcludeTitle}"`);
+  }
+
+  // Use join to get spacing between clauses right. Includes must be separated
+  // by "and" while excludes must nut. Excludes should already have "not" prepended.
+  const query = [includes.join(" and "), excludes.join(" ")].join(" ");
+
   const searchUrl = `${replacePlaceholders({
     text: rawSearchUrl,
     placeholders: {
       query: encodeURI(query),
       sort: encodeURI(sort)
     }
   })}`;
+
   const relatedMaterials = useGetRelatedMaterials({
     query,
     fields: [