Method setPreOrderIndexIfUnset

lib/ModuleGraph.js:826–833

* Sets pre order index if unset. * @param {Module} module the module * @param {number} index the index of the module * @returns {boolean} true, if the index was set

(module, index)

	 * @returns {boolean} true, if the index was set
	 */
	setPreOrderIndexIfUnset(module, index) {
		const mgm = this._getModuleGraphModule(module);
		if (mgm.preOrderIndex === null) {
			mgm.preOrderIndex = index;
			return true;
		}
		return false;
	}

	/**
	 * Sets post order index.