🐛 bug: passing frontMatterType is causing crash in nextJS

[souravdasslg]

What exactly happened?

I started using MDXTS a couple of days ago and this is working fine, but right now I got hit with a bug. On passing frontMatter type causing a crash.

import { createSource } from "mdxts";

type FrontMatter = {
    title: string
    seoTitle: string
    description: string
    abstract: string
    publishedOn: Date
    keywords: string
    isPublished: boolean
  }

export const getBlogPaths = createSource<{ frontMatter: FrontMatter}>("../_mdx/*.mdx");

The above code will work fine if I don't pass the frontMatter type.

export const getBlogPaths = createSource("../_mdx/*.mdx");

Error shown in console

TypeError: Cannot convert undefined or null to object
    at Function.entries (<anonymous>)
    at formatFrontMatterValue (webpack-internal:///(rsc)/./node_modules/mdxts/dist/src/index.js:346:27)
    at eval (webpack-internal:///(rsc)/./node_modules/mdxts/dist/src/index.js:80:35)
    at Array.map (<anonymous>)
    at eval (webpack-internal:///(rsc)/./node_modules/mdxts/dist/src/index.js:79:62)
    at Array.forEach (<anonymous>)
    at createSource (webpack-internal:///(rsc)/./node_modules/mdxts/dist/src/index.js:78:23)
    at eval (webpack-internal:///(rsc)/./app/utils/getBlogPaths.ts:10:73) {
  type: 'TypeError'
}

[souporserious]

I'm not quite sure why this is erroring since all of the front matter fields seem ok 🤔. My guess is the file being type-checked has some unexpected data. I updated the formatter here to better account for undefined and null values. Please update to 0.17.0 to try and fix, if you're still experiencing issues and can reproduce in a public repository I'm happy to take a closer look.