Adding support for quoted search strings

src/app/_pipes/parse-search-query/parse-search-query.pipe.spec.ts

@@ -36,6 +36,26 @@ describe('ParseSearchQueryPipe', () => {
     expect(pipe.transform('ham         cheese')).toEqual(new SearchParams(['ham', 'cheese'], []));
   });
 
+  it('should ignore leading spaces', () => {
+    expect(pipe.transform('     ham cheese')).toEqual(new SearchParams(['ham', 'cheese'], []));
+  });
+
+  it('should ignore trailing spaces', () => {
+    expect(pipe.transform('ham cheese   ')).toEqual(new SearchParams(['ham', 'cheese'], []));
+  });
+
+  it('should treat quoted strings as exact match', () => {
+    expect(pipe.transform('"sour cream" onions')).toEqual(new SearchParams(['sour cream', 'onions'], []));
+  });
+
+  it('should accept quoted entire query', () => {
+    expect(pipe.transform('"flourless chocolate cake"')).toEqual(new SearchParams(['flourless chocolate cake'], []));
+  });
+
+  it('should ignore unmatched double quote', () => {
+    expect(pipe.transform('"sour cream')).toEqual(new SearchParams(['sour', 'cream'], []));
+  });
+
   it('should remove keywords when other keywords contain the substrings', () => {
     expect(pipe.transform('chicken chick')).toEqual(new SearchParams(['chicken'], []));
   });

src/app/_pipes/parse-search-query/parse-search-query.pipe.ts

@@ -29,7 +29,9 @@ export class ParseSearchQueryPipe implements PipeTransform {
 const EXCLUDE_PREFIX = '-';
 
 function tokenizeQuery(query: string) {
-  let tokens = query.toLowerCase().split(/[\s,]/).filter(x => x !== '');
+  let tokens = extractQuotedStrings(query);
+  const partialQuery = removeDoubleQuotes(removeQuotedStrings(query));
+  tokens = tokens.concat(extractTokens(partialQuery));
 
   tokens = removeDuplicateTokens(tokens);
 
@@ -38,6 +40,33 @@ function tokenizeQuery(query: string) {
   return tokens;
 }
 
+function extractQuotedStrings(query: string): string[] {
+  const quotedStrings : string[] = [];
+  let stringStart: number = -1;
+  for (let i  = 0; i < query.length; i += 1) {
+    if (query[i] === '"') {
+      if (stringStart === -1) {
+        stringStart = i + 1;
+      } else {
+        quotedStrings.push(query.substr(stringStart, i - 1));
+      }
+    }
+  }
+  return quotedStrings;
+}
+
+function removeQuotedStrings(query: string): string {
+  return query.replace(/"[^"]*"/g, '').replace('"', '');
+}
+
+function removeDoubleQuotes(query: string): string {
+  return query.replace('"', '');
+}
+
+function extractTokens(query: string) : string[] {
+  return query.toLowerCase().split(/[\s,]/).filter(x => x !== '');
+}
+
 function removeSubstrings(tokens: string[]) {
   const substrings = new Set();
   // Find tokens that are contained in other tokens (e.g., "be" in "beef").