Don't infer filenames as hostnames

Author: ericallam

README.md

@@ -15,6 +15,7 @@
   - [URI strings](#uri-strings)
   - [Email address strings](#email-address-strings)
   - [Other formats](#other-formats)
+- [Roadmap](#roadmap)
 
 ## 🚀 Features
 
@@ -269,3 +270,9 @@ The following table illustrates the rest of the formats JSON Infer Types support
 | `'{ foo: 1, }'`                           | json        | json5     |
 
 Please feel free to request additional formats by opening a [Github issue](https://github.com/jsonhero-io/json-infer-types/issues)
+
+## Roadmap
+
+- Infer Firestore timestamps
+- Infer semver string
+- Infer Emoji

src/formats/hostname.ts

@@ -1,3 +1,91 @@
+import path from "path";
+
+const filenameExtensions = [
+  ".7z",
+  ".aac",
+  ".au",
+  ".avi",
+  ".bmp",
+  ".bz2",
+  ".css",
+  ".csv",
+  ".dmg",
+  ".doc",
+  ".docx",
+  ".eot",
+  ".epub",
+  ".flac",
+  ".flv",
+  ".gif",
+  ".gz",
+  ".htm",
+  ".html",
+  ".ico",
+  ".jpeg",
+  ".jpg",
+  ".js",
+  ".json",
+  ".key",
+  ".m2v",
+  ".m4a",
+  ".m4v",
+  ".m4v",
+  ".md",
+  ".mov",
+  ".mp2",
+  ".mp3",
+  ".mp4",
+  ".mpe",
+  ".mpeg",
+  ".mpeg",
+  ".mpg",
+  ".mpg",
+  ".mpv",
+  ".mxf",
+  ".numbers",
+  ".odt",
+  ".ogg",
+  ".ogv",
+  ".pages",
+  ".pdf",
+  ".png",
+  ".ppt",
+  ".pptx",
+  ".psd",
+  ".rar",
+  ".raw",
+  ".rtf",
+  ".svg",
+  ".swf",
+  ".tar",
+  ".tgz",
+  ".tif",
+  ".tiff",
+  ".ts",
+  ".tsv",
+  ".ttf",
+  ".txt",
+  ".wav",
+  ".webp",
+  ".wmv",
+  ".woff",
+  ".woff2",
+  ".xls",
+  ".xlsx",
+  ".xml",
+  ".xz",
+  ".yaml",
+  ".yml",
+  ".z",
+  ".zip",
+];
+
+function isNotFilename(value: string): boolean {
+  const extname = path.extname(value);
+
+  return extname === "" || !filenameExtensions.includes(extname);
+}
+
 export type JSONHostnameFormat = {
   name: "hostname";
   variant: "rfc1123" | "rfc5890";
@@ -42,7 +130,7 @@ function isValidHostname(value: string, allowUnderscore = false): boolean {
     return validLabel;
   });
 
-  return isValid;
+  return isValid && isNotFilename(value);
 }
 
 export function inferHostname(value: string): JSONHostnameFormat | undefined {

tests/stringFormats.test.ts

@@ -476,12 +476,15 @@ describe("hostnames", () => {
     });
   });
 
-  test.each([`${"example".repeat(36)}.com`])("%p should NOT be inferred as a hostname", (value) => {
-    expect(inferType(value)).toEqual({
-      name: "string",
-      value,
-    });
-  });
+  test.each([`${"example".repeat(36)}.com`, "Screen_Shot_2021-08-16_at_11_12_27_AM.png"])(
+    "%p should NOT be inferred as a hostname",
+    (value) => {
+      expect(inferType(value)).toEqual({
+        name: "string",
+        value,
+      });
+    },
+  );
 });
 
 describe("file sizes", () => {