@markschema/mdshape

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headers ​

What It Is ​

headers is used here as a contract-first parser powered by document-level structure checks, explicit section targeting, and boundary constraints for headers scenarios. With section(), document(), tables(), and object() in the schema, a compact markdown payload is converted into top-level keys tables without manual headers post-processing. Error cases report issue codes like missing_section, making operational diagnostics for headers flows consistent across local runs and CI.

When to Use ​

This method is a strong fit for tightening scalar constraints without redefining the base shape where deterministic headers parsing matters more than free-form flexibility. Do not default to it for very loose drafts where strict refinement would block iteration around headers; the main cost is more explicit schema maintenance to keep output deterministic. For best results, compose headers with section(), document(), tables(), and object() so headers schema intent stays readable and output remains predictable.

Input Markdown ​

md
## 9. ADVANCED BLOCK

| Metric | Target |
| --- | --- |
| Precision | >= 0.92 |

Schema ​

ts
import { md } from '@markschema/mdshape'

const section = md.section('9. ADVANCED BLOCK')

const schema = md.document({
  tables: section
    .tables(
      md.object({
        headers: md.list(md.string()).min(2),
        rows: md.list(md.list(md.string()).min(2)).min(1),
      }),
    )
    .headers(['Metric', 'Target'])
    .min(1),
})

Result ​

Success ​

json
{
  "success": true,
  "data": {
    "tables": [
      {
        "headers": [
          "Metric",
          "Target"
        ],
        "rows": [
          [
            "Precision",
            ">= 0.92"
          ]
        ]
      }
    ]
  }
}

Error ​

json
{
  "success": false,
  "error": {
    "issues": [
      {
        "code": "missing_section",
        "message": "Missing section \"9. ADVANCED BLOCK\"",
        "path": [
          "tables"
        ],
        "line": 1,
        "position": {
          "start": {
            "line": 1,
            "column": 1
          }
        }
      }
    ]
  }
}