WP_Theme_JSON::sanitize() WordPress Method

	protected static function sanitize( $input, $valid_block_names, $valid_element_names ) {
		$output = array();

		if ( ! is_array( $input ) ) {
			return $output;
		}

		$output = array_intersect_key( $input, array_flip( static::VALID_TOP_LEVEL_KEYS ) );

		// Some styles are only meant to be available at the top-level (e.g.: blockGap),
		// hence, the schema for blocks & elements should not have them.
		$styles_non_top_level = static::VALID_STYLES;
		foreach ( array_keys( $styles_non_top_level ) as $section ) {
			foreach ( array_keys( $styles_non_top_level[ $section ] ) as $prop ) {
				if ( 'top' === $styles_non_top_level[ $section ][ $prop ] ) {
					unset( $styles_non_top_level[ $section ][ $prop ] );
				}
			}
		}

		// Build the schema based on valid block & element names.
		$schema                 = array();
		$schema_styles_elements = array();
		foreach ( $valid_element_names as $element ) {
			$schema_styles_elements[ $element ] = $styles_non_top_level;
		}
		$schema_styles_blocks   = array();
		$schema_settings_blocks = array();
		foreach ( $valid_block_names as $block ) {
			$schema_settings_blocks[ $block ]           = static::VALID_SETTINGS;
			$schema_styles_blocks[ $block ]             = $styles_non_top_level;
			$schema_styles_blocks[ $block ]['elements'] = $schema_styles_elements;
		}
		$schema['styles']             = static::VALID_STYLES;
		$schema['styles']['blocks']   = $schema_styles_blocks;
		$schema['styles']['elements'] = $schema_styles_elements;
		$schema['settings']           = static::VALID_SETTINGS;
		$schema['settings']['blocks'] = $schema_settings_blocks;

		// Remove anything that's not present in the schema.
		foreach ( array( 'styles', 'settings' ) as $subtree ) {
			if ( ! isset( $input[ $subtree ] ) ) {
				continue;
			}

			if ( ! is_array( $input[ $subtree ] ) ) {
				unset( $output[ $subtree ] );
				continue;
			}

			$result = static::remove_keys_not_in_schema( $input[ $subtree ], $schema[ $subtree ] );

			if ( empty( $result ) ) {
				unset( $output[ $subtree ] );
			} else {
				$output[ $subtree ] = $result;
			}
		}

		return $output;
	}