Custom column handling

At this time, stock Notion-to-MD just drops column information.

Author: hatton

src/CustomTranformers.ts

@@ -0,0 +1,97 @@
+import { Client } from "@notionhq/client";
+import { ListBlockChildrenResponse } from "@notionhq/client/build/src/api-endpoints";
+import { NotionToMarkdown } from "notion-to-md";
+import {
+  ListBlockChildrenResponseResult,
+  ListBlockChildrenResponseResults,
+} from "notion-to-md/build/types";
+
+export function setupCustomTransformers(
+  notionToMarkdown: NotionToMarkdown,
+  notionClient: Client
+): void {
+  notionToMarkdown.setCustomTransformer(
+    "column_list",
+    (block: ListBlockChildrenResponseResult) =>
+      notionColumnListToMarkdown(notionToMarkdown, notionClient, block)
+  );
+
+  notionToMarkdown.setCustomTransformer(
+    "column",
+    (block: ListBlockChildrenResponseResult) =>
+      notionColumnToMarkdown(notionToMarkdown, notionClient, block)
+  );
+}
+
+async function notionColumnListToMarkdown(
+  notionToMarkdown: NotionToMarkdown,
+  notionClient: Client,
+  block: ListBlockChildrenResponseResult
+): Promise<string> {
+  const { id, has_children } = block as any; // "any" because the notion api type system is complex with a union that don't know how to help TS to cope with
+
+  if (!has_children) return "";
+
+  const column_list_children = await getBlockChildren(notionClient, id, 100);
+
+  const column_list_promise = column_list_children.map(
+    async column => await notionToMarkdown.blockToMarkdown(column)
+  );
+
+  const columns: string[] = await Promise.all(column_list_promise);
+
+  return `<div class='column_list'>${columns.join("\n\n")}</div>`;
+}
+
+async function notionColumnToMarkdown(
+  notionToMarkdown: NotionToMarkdown,
+  notionClient: Client,
+  block: ListBlockChildrenResponseResult
+): Promise<string> {
+  const { id, has_children } = block as any; // "any" because the notion api type system is complex with a union that don't know how to help TS to cope with
+
+  if (!has_children) return "";
+
+  const children = await getBlockChildren(notionClient, id, 100);
+
+  const childrenPromise = children.map(
+    async column => await notionToMarkdown.blockToMarkdown(column)
+  );
+
+  const childrenStrings: string[] = await Promise.all(childrenPromise);
+
+  return `<div class='column'>${childrenStrings.join("\n\n")}</div>`;
+}
+
+async function getBlockChildren(
+  notionClient: Client,
+  block_id: string,
+  totalPage: number | null
+) {
+  try {
+    const result: ListBlockChildrenResponseResults = [];
+    let pageCount = 0;
+    let start_cursor = undefined;
+
+    do {
+      // eslint-disable-next-line @typescript-eslint/no-unnecessary-type-assertion
+      const response = (await notionClient.blocks.children.list({
+        start_cursor: start_cursor,
+        block_id: block_id,
+      })) as ListBlockChildrenResponse;
+      result.push(...response.results);
+
+      start_cursor = response?.next_cursor;
+      pageCount += 1;
+    } while (
+      start_cursor != null &&
+      (totalPage == null || pageCount < totalPage)
+    );
+
+    //TODO: copied this in, what is it for? modifyNumberedListObject(result);
+    return result;
+  } catch (e) {
+    console.error(e);
+    return [];
+  }
+}

src/pull.ts

@@ -12,6 +12,7 @@ import {
 } from "./NotionImage";
 import chalk from "chalk";
 import { tweakForDocusaurus } from "./DocusaurusTweaks";
+import { setupCustomTransformers } from "./CustomTranformers";
 
 //import { FlatGuidLayoutStrategy } from "./FlatGuidLayoutStrategy";
 
@@ -43,6 +44,7 @@ export async function notionPull(options: any): Promise<void> {
 
   const notionClient = initNotionClient(options.notionToken);
   notionToMarkdown = new NotionToMarkdown({ notionClient });
+  setupCustomTransformers(notionToMarkdown, notionClient);
   layoutStrategy = new HierarchicalNamedLayoutStrategy();
   //layoutStrategy = new FlatGuidLayoutStrategy();