Fix type errors in LazySet.

I think the only place that was broken is where
we copy users from streams.

frontend_tests/node_tests/lazy_set.js

@@ -0,0 +1,23 @@
+set_global('blueslip', global.make_zblueslip());
+const LazySet = zrequire('lazy_set').LazySet;
+
+/*
+    We mostly test LazySet indirectly.  This code
+    may be short-lived, anyway, once we change
+    how we download subscribers in page_params.
+*/
+
+run_test('map', () => {
+    const ls = LazySet([1, 2]);
+
+    const triple = (n) => n * 3;
+
+    assert.deepEqual(ls.map(triple), [3, 6]);
+});
+
+run_test('conversions', () => {
+    blueslip.set_test_data('error', 'not a number');
+    const ls = LazySet([1, 2]);
+    ls.add('3');
+    assert(ls.has('3'));
+});

static/js/lazy_set.js

@@ -53,18 +53,30 @@ exports.LazySet = function (vals) {
 
     self.has = function (v) {
         make_set();
-        return self.set.has(v);
+        const val = self._clean(v);
+        return self.set.has(val);
     };
 
     self.add = function (v) {
         make_set();
-        self.set.add(v);
+        const val = self._clean(v);
+        self.set.add(val);
     };
 
     self.del = function (v) {
         make_set();
-        self.set.delete(v);
+        const val = self._clean(v);
+        self.set.delete(val);
     };
 
+    self._clean = function (v) {
+        if (typeof v !== 'number') {
+            blueslip.error('not a number');
+            return parseInt(v, 10);
+        }
+        return v;
+    };
+
+
     return self;
 };

static/js/stream_create.js

@@ -288,7 +288,8 @@ exports.show_new_stream_modal = function () {
 
         $('#user-checkboxes label.checkbox').each(function () {
             const user_elem = $(this);
-            const user_id = user_elem.attr('data-user-id');
+            const str_user_id = user_elem.attr('data-user-id');
+            const user_id = parseInt(str_user_id, 10);
 
             if (subscriber_ids.has(user_id)) {
                 user_elem.find('input').prop('checked', checked);

tools/test-js-with-node

@@ -52,6 +52,7 @@ enforce_fully_covered = {
     'static/js/keydown_util.js',
     'static/js/input_pill.js',
     'static/js/int_dict.ts',
+    'static/js/lazy_set.js',
     'static/js/list_cursor.js',
     'static/js/markdown.js',
     'static/js/message_store.js',