[WIP] Apply simplifications for stlite

frontend/app/src/App.tsx

@@ -874,7 +874,14 @@ export class App extends PureComponent<Props, State> {
         const pagePath = viewingMainPage ? "" : newPageName
         const pageUrl = `${basePathPrefix}/${pagePath}${qs}`
 
-        window.history.pushState({}, "", pageUrl)
+        // Remove the trailing slash unless it results in an empty string to avoid undesirable path overrides
+        // such as "/test.html" -> "/test.html/". These are problematic for uses with stlite.
+        const trimmedPageUrl =
+          pageUrl.endsWith("/") && pageUrl !== "/"
+            ? pageUrl.slice(0, -1)
+            : pageUrl
+
+        window.history.pushState({}, "", trimmedPageUrl)
       }
     }
 

frontend/lib/src/components/elements/ImageList/ImageList.tsx

@@ -54,6 +54,7 @@ export function ImageList({
   height,
   endpoints,
 }: ImageListProps): ReactElement {
+  const images = element.imgs
   // The width field in the proto sets the image width, but has special
   // cases for -1, -2, and -3.
   let containerWidth: number | undefined
@@ -91,7 +92,7 @@ export function ImageList({
 
   return (
     <StyledImageList style={{ width }}>
-      {element.imgs.map((iimage: IImage, idx: number): ReactElement => {
+      {images.map((iimage: IImage, idx: number): ReactElement => {
         const image = iimage as ImageProto
         return (
           <StyledImageContainer key={idx} data-testid="stImage">

frontend/lib/src/components/widgets/DataFrame/columns/utils.ts

@@ -278,6 +278,12 @@ export function toSafeArray(data: any): any[] {
     return [data]
   }
 
+  if (data instanceof Uint8Array) {
+    // Uint8Array might be used to represent string (json) data
+    // which needs to be decoded to a string here.
+    data = new TextDecoder("utf-8").decode(data)
+  }
+
   if (typeof data === "string") {
     if (data === "") {
       // Empty string

frontend/lib/src/dataframes/Quiver.ts

@@ -1002,7 +1002,9 @@ but was expecting \`${JSON.stringify(expectedIndexTypes)}\`.
   public static getTypeName(type: Type): IndexTypeName | string {
     // For `PeriodType` and `IntervalType` types are kept in `numpy_type`,
     // for the rest of the indexes in `pandas_type`.
-    return type.pandas_type === "object" ? type.numpy_type : type.pandas_type
+    const typeName =
+      type.pandas_type === "object" ? type.numpy_type : type.pandas_type
+    return typeName.toLowerCase().trim()
   }
 
   /** Takes the data and it's type and nicely formats it. */

frontend/lib/src/util/UriUtil.ts

@@ -48,9 +48,14 @@ export function getWindowBaseUriParts(): BaseUriParts {
     port = isHttps() ? 443 : 80
   }
 
-  const basePath = window.location.pathname
-    .replace(FINAL_SLASH_RE, "")
-    .replace(INITIAL_SLASH_RE, "")
+  // "about:blank" is sometimes as href when Streamlit is running
+  // within an iframe with inline code, e.g. in the case of stlite.
+  const basePath =
+    window.location.href === "about:blank"
+      ? ""
+      : window.location.pathname
+          .replace(FINAL_SLASH_RE, "")
+          .replace(INITIAL_SLASH_RE, "")
 
   return { host, port, basePath }
 }

lib/streamlit/elements/lib/column_config_utils.py

@@ -349,7 +349,7 @@ def _determine_data_kind(
 
 
 def determine_dataframe_schema(
-    data_df: pd.DataFrame, arrow_schema: pa.Schema
+    data_df: pd.DataFrame, arrow_schema: Optional[pa.Schema]
 ) -> DataframeSchema:
     """Determine the schema of a dataframe.
 
@@ -378,7 +378,7 @@ def determine_dataframe_schema(
     for i, column in enumerate(data_df.items()):
         column_name, column_data = column
         dataframe_schema[column_name] = _determine_data_kind(
-            column_data, arrow_schema.field(i)
+            column_data, arrow_schema.field(i) if arrow_schema else None
         )
     return dataframe_schema