create an auto generate filed in Collections like updated: last_edit_time when a item is updated

[StevePhuc]

What is is best way to create create an auto generate filed in Collections like updated so each time a content items it updated it will update this field updated: last_edit_time
I check the document there is
https://velite.js.org/guide/define-collections#schema-transform-computed-fields
https://velite.js.org/reference/config#prepare
but not sure how to use them do do this.

can anyone give some hint. thanks.

[zce]

new recipe in docs: https://velite.js.org/guide/last-modified

Last Modified Schema

Based on file stat

const timestamp = () =>
  s.custom<string | undefined>(i => i === undefined || typeof i === 'string').transform<string>(async (value, { meta, addIssue }) => {
    if (value != null) {
      addIssue({ fatal: false, code: 'custom', message: '`s.timestamp()` schema will resolve the file modified timestamp' })
    }

    const stats = await stat(meta.path)
    return stats.mtime.toISOString()
  })

// use it in your schema
const posts = defineCollection({
  // ...
  schema: {
    // ...
    lastModified: timestamp()
  }
})

Based on git timestamp

const execAsync = promisify(exec)

const timestamp = () =>
  s.custom<string | undefined>(i => i === undefined || typeof i === 'string').transform<string>(async (value, { meta, addIssue }) => {
    if (value != null) {
      addIssue({ fatal: false, code: 'custom', message: '`s.timestamp()` schema will resolve the value from `git log -1 --format=%cd`' })
    }
    const { stdout } = await execAsync(`git log -1 --format=%cd ${meta.path}`)
    return new Date(stdout).toISOString()
  })

// use it in your schema
const posts = defineCollection({
  // ...
  schema: {
    // ...
    lastModified: timestamp()
  }
})

[StevePhuc]

wow so quick. thank you so much.

[mupinnn]

Thank you for the recipe. It's exactly what I need for the git timestamp. But, I'm coming into a problem when running the build.

If I write it as required, the build will fail if the --strict flag is present. I think that is because I need to explicitly write the lastModified property in the front matter of the markdown. In development, it's fine because strict is false.

If I write it as optional timestamp().optional(), I'm using Next.js, and the build will fail because I'm formatting an undefined date that leads to a pre-render error. Because I set it optional. The property would not be present if I hadn't explicitly written it.

Is there a way to put this custom schema into a computed field or something not required to be written explicitly in the markdown, JSON, or YAML?

[zce]

@mupinnn

Strict mode will not produce errors. Currently, strict mode will only fail and exit when there is a warning, and there will be no more restrictions.

If you still have problems, you can open a new issue and provide a reproducible repository. I will be happy to help you solve this problem.