# Type Built-ins

| Function | Description | Meta |
| --- | --- | --- |
| `is_array` | `result := is_array(x)`  Returns `true` if the input value is an array.  **Arguments:**  `x` (any)  input value  **Returns:**  `result` (boolean)  `true` if `x` is an array, `false` otherwise. | Wasm |
| `is_boolean` | `result := is_boolean(x)`  Returns `true` if the input value is a boolean.  **Arguments:**  `x` (any)  input value  **Returns:**  `result` (boolean)  `true` if `x` is an boolean, `false` otherwise. | Wasm |
| `is_null` | `result := is_null(x)`  Returns `true` if the input value is null.  **Arguments:**  `x` (any)  input value  **Returns:**  `result` (boolean)  `true` if `x` is null, `false` otherwise. | Wasm |
| `is_number` | `result := is_number(x)`  Returns `true` if the input value is a number.  **Arguments:**  `x` (any)  input value  **Returns:**  `result` (boolean)  `true` if `x` is a number, `false` otherwise. | Wasm |
| `is_object` | `result := is_object(x)`  Returns true if the input value is an object  **Arguments:**  `x` (any)  input value  **Returns:**  `result` (boolean)  `true` if `x` is an object, `false` otherwise. | Wasm |
| `is_set` | `result := is_set(x)`  Returns `true` if the input value is a set.  **Arguments:**  `x` (any)  input value  **Returns:**  `result` (boolean)  `true` if `x` is a set, `false` otherwise. | Wasm |
| `is_string` | `result := is_string(x)`  Returns `true` if the input value is a string.  **Arguments:**  `x` (any)  input value  **Returns:**  `result` (boolean)  `true` if `x` is a string, `false` otherwise. | Wasm |
| `type_name` | `type := type_name(x)`  Returns the type of its input value.  **Arguments:**  `x` (any)  input value  **Returns:**  `type` (string)  one of "null", "boolean", "number", "string", "array", "object", "set" | Wasm |