public function sanitize_field( $posted_value, $field ) {

		$map = array(
			'email'    => 'sanitize_email',
			'number'   => array( $this, 'sanitize_field_number' ),
			'tel'      => array( $this, 'sanitize_field_tel' ),
			'textarea' => 'sanitize_textarea_field',
			'url'      => 'esc_url_raw',
		);

		$func = isset( $map[ $field['type'] ] ) ? $map[ $field['type'] ] : 'sanitize_text_field';

		// Turn the submitted value into array, so to unify sanitization of scalar and array posted values.
		$to_sanitize = is_array( $posted_value ) ? $posted_value : array( $posted_value );
		$sanitized   = array();

		foreach ( $to_sanitize as $value ) {
			$sanitized[] = trim( call_user_func( $func, $value ) );
		}

		return is_array( $posted_value ) ? $sanitized : $sanitized[0];

	}