hashchange: Go to home page for bogus narrows.

This was the original intent of the code, and I think
it's the right behavior.

frontend_tests/node_tests/hash_util.js

@@ -69,10 +69,9 @@ run_test('test_parse_narrow', () => {
         [{negated: false, operator: 'stream', operand: '11-social'}]
     );
 
-    // This should probably return undefined.
-    assert.deepEqual(
+    assert.equal(
         hash_util.parse_narrow(['narrow', 'BOGUS']),
-        [{negated: false, operator: 'BOGUS', operand: ''}]
+        undefined
     );
 });
 

static/js/hash_util.js

@@ -133,23 +133,25 @@ exports.parse_narrow = function (hash) {
     for (i = 1; i < hash.length; i += 2) {
         // We don't construct URLs with an odd number of components,
         // but the user might write one.
-        try {
-            var operator = exports.decodeHashComponent(hash[i]);
-            // Do not parse further if empty operator encountered.
-            if (operator === '') {
-                break;
-            }
+        var operator = exports.decodeHashComponent(hash[i]);
+        // Do not parse further if empty operator encountered.
+        if (operator === '') {
+            break;
+        }
 
-            var operand  = exports.decode_operand(operator, hash[i + 1] || '');
-            var negated = false;
-            if (operator[0] === '-') {
-                negated = true;
-                operator = operator.slice(1);
-            }
-            operators.push({negated: negated, operator: operator, operand: operand});
-        } catch (err) {
+        var raw_operand = hash[i + 1];
+
+        if (!raw_operand) {
             return;
         }
+
+        var operand  = exports.decode_operand(operator, raw_operand);
+        var negated = false;
+        if (operator[0] === '-') {
+            negated = true;
+            operator = operator.slice(1);
+        }
+        operators.push({negated: negated, operator: operator, operand: operand});
     }
     return operators;
 };

tools/test-js-with-node

@@ -44,7 +44,7 @@ enforce_fully_covered = {
     'static/js/fenced_code.js',
     'static/js/fetch_status.js',
     'static/js/filter.js',
-    # 'static/js/hash_util.js',
+    'static/js/hash_util.js',
     'static/js/keydown_util.js',
     'static/js/input_pill.js',
     'static/js/list_cursor.js',