filter: Eliminate a few "subject" references.

This continues the effort to isolate "subject" references
to util calls.

Also, we fix a comment.

Finally, we use canonicalized operators in a switch
statement.

frontend_tests/node_tests/filter.js

@@ -161,6 +161,7 @@ run_test('canonicalizations', () => {
     assert.equal(Filter.canonicalize_operator('Is'), 'is');
     assert.equal(Filter.canonicalize_operator('Stream'), 'stream');
     assert.equal(Filter.canonicalize_operator('Subject'), 'topic');
+    assert.equal(Filter.canonicalize_operator('FROM'), 'sender');
 
     var term;
     term = Filter.canonicalize_term({operator: 'Stream', operand: 'Denmark'});

frontend_tests/node_tests/narrow_activate.js

@@ -7,6 +7,7 @@ zrequire('MessageListData', 'js/message_list_data');
 zrequire('unread');
 zrequire('narrow');
 zrequire('search_pill');
+zrequire('util');
 
 set_global('blueslip', {});
 set_global('channel', {});
@@ -27,7 +28,6 @@ set_global('tab_bar', {});
 set_global('top_left_corner', {});
 set_global('typing_events', {});
 set_global('ui_util', {});
-set_global('util', {});
 set_global('unread_ops', {});
 set_global('search_pill_widget', {
     widget: {

frontend_tests/node_tests/narrow_local.js

@@ -3,6 +3,7 @@ zrequire('MessageListData', 'js/message_list_data');
 zrequire('narrow_state');
 zrequire('narrow');
 zrequire('stream_data');
+zrequire('util');
 
 set_global('message_list', {});
 set_global('muting', {

frontend_tests/node_tests/narrow_state.js

@@ -2,6 +2,7 @@ zrequire('people');
 zrequire('Filter', 'js/filter');
 zrequire('stream_data');
 zrequire('narrow_state');
+zrequire('util');
 
 set_global('blueslip', global.make_zblueslip());
 set_global('page_params', {});

frontend_tests/node_tests/top_left_corner.js

@@ -3,6 +3,7 @@ set_global('$', global.make_zjquery());
 zrequire('Filter', 'js/filter');
 zrequire('unread_ui');
 zrequire('people');
+zrequire('util');
 
 zrequire('top_left_corner');
 

static/js/filter.js

@@ -154,12 +154,15 @@ function Filter(operators) {
     }
 }
 
-var canonical_operators = {from: "sender", subject: "topic"};
-
 Filter.canonicalize_operator = function (operator) {
     operator = operator.toLowerCase();
-    if (canonical_operators.hasOwnProperty(operator)) {
-        return canonical_operators[operator];
+
+    if (operator === 'from') {
+        return 'sender';
+    }
+
+    if (util.is_topic_synonym(operator)) {
+        return 'topic';
     }
     return operator;
 };
@@ -298,7 +301,7 @@ Filter.parse = function (str) {
 /* Convert a list of operators to a string.
    Each operator is a key-value pair like
 
-       ['subject', 'my amazing subject']
+       ['topic', 'my amazing topic']
 
    These are not keys in a JavaScript object, because we
    might need to support multiple operators of the same type.
@@ -575,6 +578,8 @@ Filter.sorted_term_types = function (term_types) {
 Filter.operator_to_prefix = function (operator, negated) {
     var verb;
 
+    operator = Filter.canonicalize_operator(operator);
+
     if (operator === 'search') {
         return negated ? 'exclude' : 'search for';
     }
@@ -595,11 +600,9 @@ Filter.operator_to_prefix = function (operator, negated) {
     case 'id':
         return verb + 'message ID';
 
-    case 'subject':
     case 'topic':
         return verb + 'topic';
 
-    case 'from':
     case 'sender':
         return verb + 'sent by';
 

static/js/util.js

@@ -311,6 +311,10 @@ exports.get_topic = function (obj) {
     return obj.subject;
 };
 
+exports.is_topic_synonym = function (operator) {
+    return operator === 'subject';
+};
+
 return exports;
 
 }());