ValueInspector

ValueInspector::isBlank(mixed $value): bool returns true for exactly three values: null, '' and [].

use Derafu\Value\ValueInspector;

ValueInspector::isBlank(null);   // true
ValueInspector::isBlank('');     // true
ValueInspector::isBlank([]);     // true
ValueInspector::isBlank(false);  // false
ValueInspector::isBlank(0);      // false
ValueInspector::isBlank('0');    // false
ValueInspector::isBlank('   ');  // false
ValueInspector::isBlank([null]); // false

This is an inspection of the supplied value, not PHP’s empty() behavior. It does not determine whether a key exists, whether a value was supplied by a caller or whether an application requires it.

Whitespace is not trimmed, array elements are not inspected recursively, and objects are neither counted nor converted to text. Even an empty Countable object is treated as an object rather than as [].

Inspection and Interpretation

The parser performs conversions; the inspector does not:

use Derafu\Value\ValueInspector;
use Derafu\Value\ValueParser;

ValueInspector::isBlank('null'); // false; text exists
ValueParser::parse('null');      // null; a recognized literal
ValueInspector::isBlank(' ');    // false; the string contains a space
ValueParser::parse(' ');         // false; boolean interpretation

Choose the operation explicitly. A blank check does not imply a type conversion, and parsing does not decide application-level requiredness.