renderSchema

Render a SchemaNode tree as compact, human-readable text.

Signature

function renderSchema(node: SchemaNode, options?: RenderOptions): string;

Options

Option	Type	Default	Description
showStringLengths	boolean	false	Show character counts, e.g. string(21) instead of string.

How rendering works

The renderer walks the SchemaNode tree and makes formatting decisions at each level:

• Primitives — rendered as their type name: string, number, boolean, null
• Objects — rendered inline {key: type} if under 80 chars, otherwise expanded with dot-paths
• Arrays — show element count and item type: array(25) of {id: number}
• Unions — show all variants with | and counts: {id: number}(×3) | string

Try it: Primitives

All four primitive types rendered on separate lines.

renderSchema()

mode

depth 10

lengths

Input

{
  "name": "Alice",
  "age": 30,
  "active": true,
  "deleted": null
}

{ "name": "Alice", "age": 30, "active": true, "deleted": null }

Output

Try it: Inline Object (< 80 chars)

Small nested objects stay on one line: meta: {page: number, total: number}.

renderSchema()

mode

depth 10

lengths

Input

{
  "meta": { "page": 1, "total": 50 }
}

{ "meta": { "page": 1, "total": 50 } }

Output

Try it: Dot-Path Expansion (> 80 chars)

When a nested object is too wide for inline, keys are expanded with dot-joined paths like product.name: string.

renderSchema()

mode

depth 10

lengths

Input

{
  "product": {
    "name": "Widget X",
    "brand": "Acme",
    "price": 999,
    "stock": 50,
    "category": "gadgets",
    "sku": "ABC123"
  }
}

{ "product": { "name": "Widget X", "brand": "Acme", "price": 999, "stock": 50, "category": "gadgets", "sku": "ABC123" } }

Output

Try it: Nested Inline

When inner objects are small enough, they nest inline: product: {details: {manufacturer: string, model: string}, price: number}.

renderSchema()

mode

depth 10

lengths

Input

{
  "product": {
    "details": { "manufacturer": "Acme", "model": "Widget X" },
    "price": 999
  }
}

{ "product": { "details": { "manufacturer": "Acme", "model": "Widget X" }, "price": 999 } }

Output

Try it: Array of Objects (Inline)

Array items that fit under 120 chars render inline.

renderSchema()

mode

depth 10

lengths

Input

{
  "users": [
    { "id": 1, "name": "Alice" },
    { "id": 2, "name": "Bob" }
  ]
}

{ "users": [ { "id": 1, "name": "Alice" }, { "id": 2, "name": "Bob" } ] }

Output

Try it: Array of Objects (Multi-line)

When array items have many keys (> 120 chars inline), they expand with indented keys inside { }.

renderSchema()

mode

depth 10

lengths

Input

{
  "users": [
    {
      "id": 1,
      "first_name": "Alice",
      "last_name": "Smith",
      "email": "alice@test.com",
      "phone": "+1234567890",
      "role": "admin",
      "dept": "engineering",
      "status": "active"
    }
  ]
}

{ "users": [ { "id": 1, "first_name": "Alice", "last_name": "Smith", "email": "alice@test.com", "phone": "+1234567890", "role": "admin", "dept": "engineering", "status": "active" } ] }

Output

Try it: Optional Keys

Keys that appear in only some array elements are tagged (optional). Here name is in 1 of 2 elements.

renderSchema()

mode

depth 10

lengths

Input

[
  { "id": 1, "name": "Alice" },
  { "id": 2 }
]

[ { "id": 1, "name": "Alice" }, { "id": 2 } ]

Output

Try it: Varying Array Sizes

When nested arrays have different lengths across elements, the count is replaced with array(varying sizes).

renderSchema()

mode

depth 10

lengths

Input

[
  { "tags": ["a", "b", "c"] },
  { "tags": ["x"] }
]

[ { "tags": ["a", "b", "c"] }, { "tags": ["x"] } ]

Output

Try it: Union with Variant Counts

Mixed-type arrays show each type with |. Types appearing multiple times show a count like (×3). Switch to exhaustive mode to catch all types.

renderSchema()

mode

depth 10

lengths

Input

[
  { "id": 1 },
  { "id": 2 },
  { "id": 3 },
  "stray",
  [99]
]

[ { "id": 1 }, { "id": 2 }, { "id": 3 }, "stray", [99] ]

Output

Try it: String Lengths

Toggle showStringLengths to see character counts on string fields, e.g. string(5).

renderSchema()

mode

depth 10

lengths

Input

{
  "data": {
    "users": [
      { "id": 1, "name": "Alice", "email": "alice@example.com" },
      { "id": 2, "name": "Bob", "email": "bob@example.com" }
    ]
  },
  "meta": { "page": 1, "total": 50, "per_page": 25 }
}

{ "data": { "users": [ { "id": 1, "name": "Alice", "email": "alice@example.com" }, { "id": 2, "name": "Bob", "email": "bob@example.com" } ] }, "meta": { "page": 1, "total": 50, "per_page": 25 } }

Output

Try it: Empty Containers

Empty arrays show empty, empty objects show {}.

renderSchema()

mode

depth 10

lengths

Input

{
  "items": [],
  "config": {}
}

{ "items": [], "config": {} }

Output

Output Format

The output is not standard JSON Schema. It's a compact text format designed for minimal tokens:

data.users: array(25) of {id: number, name: string, email: string}
meta.page: number
meta.total: number

Formatting rules

Condition	Format	Example
Root object	Keys expanded, one per line	name: string
Nested object < 80 chars	Inline	meta: {page: number, total: number}
Nested object >= 80 chars	Dot-path expansion	product.name: string
Array items (object) < 120 chars	Inline	array(5) of {id: number, name: string}
Array items (object) >= 120 chars	Multi-line with indentation	array(1) of {\n id: number\n ...}
Array items (non-object)	Always inline	array(3) of string
Optional keys	Tagged	(optional) string
Varying array sizes	Count replaced	array(varying sizes) of string
Union types	Pipe-separated with counts	{id: number}(×3) | string
Empty array	Tagged	array(0) empty
Empty object	Braces	{}