> ## Documentation Index
> Fetch the complete documentation index at: https://docs.sure-developer.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Validator

> Runtime schema validation for tables, primitives, callbacks, ranges, and enum-like values

# Validator

The `validator` module creates small schema objects that expose `parse(data)`. A successful parse returns `true`. A failed parse raises `Validation Error: ...`, so wrap user-controlled inputs with `pcall` when you want to handle errors without stopping execution.

```lua theme={"dark"}
local v = sure.getModule('validator')
```

## Basic schema

<CodeGroup>
  ```lua Create a schema theme={"dark"}
  local itemSchema = v.object({
    name = v.string().required('Item name is required'),
    amount = v.integer().min(1).max(100),
    metadata = v.object({
      label = v.string(),
      temporary = v.boolean()
    })
  })
  ```

  ```lua Parse data theme={"dark"}
  local ok, err = pcall(function()
    itemSchema.parse({
      name = 'bread',
      amount = 2,
      metadata = {
        label = 'Bread',
        temporary = false
      }
    })
  end)

  if not ok then
    print(err)
  end
  ```
</CodeGroup>

## Rules

<ParamField path="required(message?)" type="function">
  Marks a value as required. When `message` is provided, that message overrides the default missing-field error.
</ParamField>

<ParamField path="message(message)" type="function">
  Sets a custom error message for the rule. The message is used when type or custom checks fail.
</ParamField>

<ParamField path="min(value)" type="function">
  Requires a numeric value to be greater than or equal to `value`.
</ParamField>

<ParamField path="max(value)" type="function">
  Requires a numeric value to be less than or equal to `value`.
</ParamField>

<ParamField path="between(min, max)" type="function">
  Applies both `min(min)` and `max(max)`.
</ParamField>

<ParamField path="oneOf(values)" type="function">
  Requires the parsed value to equal one entry in the given array.
</ParamField>

## Types

| Builder             | Accepts                                               |
| ------------------- | ----------------------------------------------------- |
| `v.object(fields)`  | A Lua table with named fields.                        |
| `v.array(itemRule)` | A Lua array table where every item passes `itemRule`. |
| `v.string()`        | Lua `string`.                                         |
| `v.number()`        | Lua `number`.                                         |
| `v.integer()`       | Lua `number` with no fractional part.                 |
| `v.boolean()`       | Lua `boolean`, including `false`.                     |
| `v.callback()`      | Lua `function`.                                       |

## Nested example

```lua theme={"dark"}
local rewardSchema = v.object({
  account = v.string().oneOf({ 'money', 'bank', 'black_money' }).required(),
  items = v.array(v.object({
    name = v.string().required(),
    amount = v.integer().min(1)
  }))
})

rewardSchema.parse({
  account = 'bank',
  items = {
    { name = 'bread', amount = 2 },
    { name = 'water', amount = 1 }
  }
})
```

<Warning>
  `parse` raises errors by design. Use `pcall` when validating network input, command arguments, or config edited by other people.
</Warning>