@markschema/mdshape

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default ​

Type: wrappers

Signature: default(value)

What It Is ​

This method page uses default(value) to enforce document-level structure checks, explicit section targeting, and typed field extraction over markdown content in default use cases. In practice, 1 h1 heading, 1 h2 section, and list content is validated and emitted as top-level keys meta using document(), section(), fields(), and string() under default rules. When constraints are broken, issue codes like missing_section identify exactly which default node failed and why.

When to Use ​

Choose default(value) for typed markdown parsing with deterministic contracts, especially when default authoring rules must remain stable across teams. Skip it in exploratory drafts that intentionally avoid strict validation workflows for default, since key-level strictness that improves typing but rejects ad-hoc variations. Combining it with document(), section(), fields(), and string() yields predictable default parsing, clearer errors, and easier runtime integration.

default(value) ​

Input Markdown ​

md
## 1. META

- Alias: ALEX

Schema ​

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

const schema = md.document({
  meta: md.section('1. META').fields({
    Alias: md.string().optional().default('UNKNOWN'),
    Region: md.string().optional().default('us-east-1'),
  }),
})

Result ​

Success ​

json
{
  "success": true,
  "data": {
    "meta": {
      "Alias": "ALEX",
      "Region": "us-east-1"
    }
  }
}

Error ​

Failure trigger: The input violates one or more constraints declared in the schema; use issues[].path and issues[].code to locate the exact failing node.

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