feat: Default slug to notion-page id

Author: hatton

README.md

@@ -79,6 +79,10 @@ One of the big attractions of Notion for large documentation projects is that yo
 
 ![image](https://user-images.githubusercontent.com/8448/168929668-f83d7c86-75d2-48e9-940c-84c5268a2854.png)
 
+## Slugs
+
+By default, pages will be given a slug based on the Notion id. For a human-readable URL, add a notion property named `Slug` and enter values in there.
+
 ## Known Limitations
 
 docu-notion is not doing anything smart with regards to previously Published but now not Published documents. All it does is ignore every Notion document that doesn't have `status == Publish`. So if the old version of the document is still in your file tree when your static site generator (e.g. Docusaurus) runs, then it will appear on your website. If it isn't there, it won't. If you rename directories or move the document, docu-notion will not realize this and will delete the previously published markdown file.

src/NotionPage.ts

@@ -100,13 +100,40 @@ export class NotionPage {
   private get name(): string {
     return this.getPlainTextProperty("Name", "name missing");
   }
-  public get slug(): string {
+
+  private explicitSlug(): string | undefined {
     const explicitSlug = this.getPlainTextProperty("Slug", "");
-    if (explicitSlug) return explicitSlug;
-    return encodeURIComponent(this.nameOrTitle.replaceAll(" ", "-"))
-      .replaceAll("%3A", "-")
-      .replaceAll("--", "-");
+    if (explicitSlug) {
+      if (explicitSlug === "/") return explicitSlug; // the root page
+      else
+        return (
+          "/" +
+          encodeURIComponent(
+            explicitSlug
+              .replace(/^\//, "")
+              // If for some reason someone types in a slug with special characters,
+              //we really don't want to see ugly entities in the URL, so first
+              // we replace a bunch of likely suspects with dashes. This will not
+              // adequately handle the case where there is one pag with slug:"foo-bar"
+              // and another with "foo?bar". Both will come out "foo-bar"
+              .replaceAll(" ", "-")
+              .replaceAll("?", "-")
+              .replaceAll("/", "-")
+              .replaceAll("#", "-")
+              .replaceAll("&", "-")
+              .replaceAll("%", "-")
+              // remove consecutive dashes
+              .replaceAll("--", "-")
+          )
+        );
+      return undefined; // this page has no slug property
+    }
   }
+
+  public get slug(): string {
+    return this.explicitSlug() ?? "/" + this.pageId;
+  }
+
   public get keywords(): string | undefined {
     return this.getPlainTextProperty("Keywords", "");
   }