fix multiselect combobox

go/vdom/vnode_test.go

@@ -0,0 +1,46 @@
+package vdom
+
+import (
+	"strings"
+	"testing"
+)
+
+// A boolean DOM property is a trap in HTML: the attribute's PRESENCE is what means
+// true. checked="false" is a ticked checkbox — the value is not even read. So a false
+// boolean prop must be omitted entirely, and a true one written bare.
+func TestBoolPropSSR(t *testing.T) {
+	ticked := RenderHTML(Input(Attr("type", "checkbox"), BoolProp("checked", true)))
+	if !strings.Contains(ticked, " checked") {
+		t.Errorf("a checked box did not render the attribute: %s", ticked)
+	}
+	if strings.Contains(ticked, `checked="`) {
+		t.Errorf("a boolean attribute must be bare, not valued: %s", ticked)
+	}
+
+	unticked := RenderHTML(Input(Attr("type", "checkbox"), BoolProp("checked", false)))
+	if strings.Contains(unticked, "checked") {
+		t.Errorf(`an unchecked box must omit the attribute entirely — checked="false" renders as TICKED: %s`, unticked)
+	}
+}
+
+// Non-boolean props keep their values: an input's value is a string, and dropping it
+// when empty would be just as wrong as writing checked="false".
+func TestValuePropSSRKeepsItsValue(t *testing.T) {
+	got := RenderHTML(Input(Prop("value", "false")))
+	if !strings.Contains(got, `value="false"`) {
+		t.Errorf(`value="false" is a string, not a boolean, and must survive: %s`, got)
+	}
+}
+
+func TestIsBoolProp(t *testing.T) {
+	for _, k := range []string{"checked", "disabled", "selected", "open"} {
+		if !IsBoolProp(k) {
+			t.Errorf("%q should be known as a boolean property — the reconciler writes it as a string otherwise", k)
+		}
+	}
+	for _, k := range []string{"value", "className", "id"} {
+		if IsBoolProp(k) {
+			t.Errorf("%q is not a boolean property", k)
+		}
+	}
+}