js: Convert _.clone(a) to { ...a } or a.slice().

Signed-off-by: Anders Kaseorg <anders@zulipchat.com>

frontend_tests/node_tests/dispatch.js

@@ -888,11 +888,11 @@ with_overrides(function (override) {
     // realm
     function test_realm_boolean(event, parameter_name) {
         page_params[parameter_name] = true;
-        event = _.clone(event);
+        event = { ...event };
         event.value = false;
         dispatch(event);
         assert.equal(page_params[parameter_name], false);
-        event = _.clone(event);
+        event = { ...event };
         event.value = true;
         dispatch(event);
         assert.equal(page_params[parameter_name], true);

frontend_tests/node_tests/drafts.js

@@ -122,9 +122,9 @@ run_test('draft_model', () => {
     localStorage.clear();
     (function test_addDraft() {
         stub_timestamp(1, function () {
-            const expected = _.clone(draft_1);
+            const expected = { ...draft_1 };
             expected.updatedAt = 1;
-            const id = draft_model.addDraft(_.clone(draft_1));
+            const id = draft_model.addDraft({ ...draft_1 });
 
             assert.deepEqual(ls.get("drafts")[id], expected);
         });
@@ -134,9 +134,9 @@ run_test('draft_model', () => {
     (function test_editDraft() {
         stub_timestamp(2, function () {
             ls.set("drafts", { id1: draft_1 });
-            const expected = _.clone(draft_2);
+            const expected = { ...draft_2 };
             expected.updatedAt = 2;
-            draft_model.editDraft("id1", _.clone(draft_2));
+            draft_model.editDraft("id1", { ...draft_2 });
 
             assert.deepEqual(ls.get("drafts").id1, expected);
         });

frontend_tests/node_tests/general.js

@@ -110,9 +110,7 @@ zrequire('topic_data');
 zrequire('message_store');
 
 run_test('message_store', () => {
-    // Our test runner automatically sets _ for us.
-    // See http://underscorejs.org/ for help on that library.
-    const in_message = _.clone(messages.isaac_to_denmark_stream);
+    const in_message = { ...messages.isaac_to_denmark_stream };
 
     assert.equal(in_message.alerted, undefined);
     message_store.set_message_booleans(in_message);
@@ -139,7 +137,7 @@ run_test('unread', () => {
 
     assert.equal(unread.num_unread_for_topic(stream_id, topic_name), 0);
 
-    const in_message = _.clone(messages.isaac_to_denmark_stream);
+    const in_message = { ...messages.isaac_to_denmark_stream };
     message_store.set_message_booleans(in_message);
 
     unread.process_loaded_messages([in_message]);

frontend_tests/node_tests/widgetize.js

@@ -54,7 +54,7 @@ run_test('activate', () => {
     ];
 
     const opts = {
-        events: _.clone(events),
+        events: events.slice(),
         extra_data: '',
         message: {
             id: 2001,

static/js/filter.js

@@ -488,7 +488,7 @@ Filter.prototype = {
 
     filter_with_new_topic: function (new_topic) {
         const terms = this._operators.map(term => {
-            const new_term = _.clone(term);
+            const new_term = { ...term };
             if (new_term.operator === 'topic' && !new_term.negated) {
                 new_term.operand = new_topic;
             }
@@ -626,7 +626,7 @@ Filter.sorted_term_types = function (term_types) {
         return util.strcmp(a, b);
     }
 
-    return _.clone(term_types).sort(compare);
+    return term_types.slice().sort(compare);
 };
 
 Filter.operator_to_prefix = function (operator, negated) {