# Interface: HistoryManagerInterface (/pixi-vn/index/interfaces/HistoryManagerInterface) Defined in: [src/history/interfaces/HistoryManagerInterface.ts:13](https://github.com/DRincs-Productions/pixi-vn/blob/5bb5bb1f92e38998ea2f477b600168d8da3ece19/src/history/interfaces/HistoryManagerInterface.ts#L13) ## Properties [#properties] ### back [#back] \> **back**: (`props`, `options?`) => `Promise`\<[`StepLabelResultType`](/pixi-vn/index/type-aliases/StepLabelResultType)> Defined in: [src/history/interfaces/HistoryManagerInterface.ts:73](https://github.com/DRincs-Productions/pixi-vn/blob/5bb5bb1f92e38998ea2f477b600168d8da3ece19/src/history/interfaces/HistoryManagerInterface.ts#L73) Go back to the last step and add it to the history. #### Parameters [#parameters] ##### props [#props] `StepLabelProps` The step label properties. ##### options? [#options] The navigation options. ###### steps? [#steps] `number` The number of steps to go back. Must be greater than 0. **Default** ```ts 1 ``` #### Returns [#returns] `Promise`\<[`StepLabelResultType`](/pixi-vn/index/type-aliases/StepLabelResultType)> *** ### canGoBack [#cangoback] \> `readonly` **canGoBack**: `boolean` Defined in: [src/history/interfaces/HistoryManagerInterface.ts:89](https://github.com/DRincs-Productions/pixi-vn/blob/5bb5bb1f92e38998ea2f477b600168d8da3ece19/src/history/interfaces/HistoryManagerInterface.ts#L89) Return true if it is possible to go back. *** ### currentLabelHistory [#currentlabelhistory] \> `readonly` **currentLabelHistory**: [`NarrationHistory`](/pixi-vn/index/interfaces/NarrationHistory)\[] Defined in: [src/history/interfaces/HistoryManagerInterface.ts:40](https://github.com/DRincs-Productions/pixi-vn/blob/5bb5bb1f92e38998ea2f477b600168d8da3ece19/src/history/interfaces/HistoryManagerInterface.ts#L40) Get the history of the latest steps belonging to the current label and its child labels. This is effectively the current "page" of an interactive book: it starts over every time a [NarrationManagerInterface.jump](/pixi-vn/index/interfaces/NarrationManagerInterface#jump) is performed. #### Returns [#returns-1] the history of the dialogues, choices and steps *** ### currentPageParagraphs [#currentpageparagraphs] \> `readonly` **currentPageParagraphs**: [`NarrationHistory`](/pixi-vn/index/interfaces/NarrationHistory)\[]\[] Defined in: [src/history/interfaces/HistoryManagerInterface.ts:50](https://github.com/DRincs-Productions/pixi-vn/blob/5bb5bb1f92e38998ea2f477b600168d8da3ece19/src/history/interfaces/HistoryManagerInterface.ts#L50) Get the current page ([HistoryManagerInterface.currentLabelHistory](#currentlabelhistory)) split into paragraphs. A new paragraph starts every time the number of opened labels changes compared to the previous step (i.e. a [NarrationManagerInterface.call](/pixi-vn/index/interfaces/NarrationManagerInterface#call) was made, or a called label returned), using [NarrationHistory.openedLabelsNumber](/pixi-vn/index/interfaces/NarrationHistory#openedlabelsnumber). #### Returns [#returns-2] the current page as an ordered list of paragraphs, each one a list of steps *** ### diffMap [#diffmap] \> `readonly` **diffMap**: [`CachedMap`](/pixi-vn/index/classes/CachedMap)\<`number`, `Difference`\[]> Defined in: [src/history/interfaces/HistoryManagerInterface.ts:149](https://github.com/DRincs-Productions/pixi-vn/blob/5bb5bb1f92e38998ea2f477b600168d8da3ece19/src/history/interfaces/HistoryManagerInterface.ts#L149) Map that contains all the differences between the steps in the history. The differences will be used to restore a step. **Don't edit unless you're sure what you're doing.** *** ### goBackMode [#gobackmode] \> **goBackMode**: [`HistoryGoBackModeType`](/pixi-vn/index/type-aliases/HistoryGoBackModeType) Defined in: [src/history/interfaces/HistoryManagerInterface.ts:26](https://github.com/DRincs-Productions/pixi-vn/blob/5bb5bb1f92e38998ea2f477b600168d8da3ece19/src/history/interfaces/HistoryManagerInterface.ts#L26) How often a go-back-able checkpoint is recorded. #### Default [#default] "step" * `"step"`: every single narration step, matching visual-novel-style games where the player may want to undo one line/sprite change at a time. * `"paragraph"`: only when a new paragraph starts ([HistoryManagerInterface.currentPageParagraphs](#currentpageparagraphs)), a choice is proposed, or an input is requested - matching book-style narrations where undoing mid-paragraph doesn't make sense to the player. Every step within a paragraph is merged into the checkpoint that closes it out: `back()` from anywhere inside paragraph N jumps all the way to the *start* of paragraph N-1, not to wherever you were right before N began - the whole of paragraph N-1 gets replayed. *** ### lastKey [#lastkey] \> `readonly` **lastKey**: `number` | `null` Defined in: [src/history/interfaces/HistoryManagerInterface.ts:118](https://github.com/DRincs-Productions/pixi-vn/blob/5bb5bb1f92e38998ea2f477b600168d8da3ece19/src/history/interfaces/HistoryManagerInterface.ts#L118) Get the last key (id) of the history. *** ### narrationMap [#narrationmap] \> `readonly` **narrationMap**: [`CachedMap`](/pixi-vn/index/classes/CachedMap)\<`number`, [`NarrationHistory`](/pixi-vn/index/interfaces/NarrationHistory)> Defined in: [src/history/interfaces/HistoryManagerInterface.ts:155](https://github.com/DRincs-Productions/pixi-vn/blob/5bb5bb1f92e38998ea2f477b600168d8da3ece19/src/history/interfaces/HistoryManagerInterface.ts#L155) Map that contains all the narration history. **Don't edit unless you're sure what you're doing.** *** ### narrativeHistory [#narrativehistory] \> `readonly` **narrativeHistory**: [`NarrationHistory`](/pixi-vn/index/interfaces/NarrationHistory)\[] Defined in: [src/history/interfaces/HistoryManagerInterface.ts:31](https://github.com/DRincs-Productions/pixi-vn/blob/5bb5bb1f92e38998ea2f477b600168d8da3ece19/src/history/interfaces/HistoryManagerInterface.ts#L31) Get the narrative history. #### Returns [#returns-3] the history of the dialogues, choices and steps *** ### size [#size] \> `readonly` **size**: `number` Defined in: [src/history/interfaces/HistoryManagerInterface.ts:114](https://github.com/DRincs-Productions/pixi-vn/blob/5bb5bb1f92e38998ea2f477b600168d8da3ece19/src/history/interfaces/HistoryManagerInterface.ts#L114) Number of items in the history. *** ### stepLimitSaved [#steplimitsaved] \> **stepLimitSaved**: `number` Defined in: [src/history/interfaces/HistoryManagerInterface.ts:61](https://github.com/DRincs-Productions/pixi-vn/blob/5bb5bb1f92e38998ea2f477b600168d8da3ece19/src/history/interfaces/HistoryManagerInterface.ts#L61) The number of steps to keep in the history into the save file. The other older steps will be compressed will be used in [HistoryManagerInterface.narrativeHistory](#narrativehistory) to show the older dialogues. In the compressed steps, the canvas and storage information will be removed. This also means that a player, after saving and loading a save, will only be able to go back to NarrationManagerInterface.stepLimitSaved steps. If you want to keep all steps in the history, you can set this value to Infinity. *** ### stepsInfoMap [#stepsinfomap] \> `readonly` **stepsInfoMap**: [`CachedMap`](/pixi-vn/index/classes/CachedMap)\<`number`, `Omit`\<[`HistoryStep`](/pixi-vn/index/interfaces/HistoryStep), `"diff"`>> Defined in: [src/history/interfaces/HistoryManagerInterface.ts:142](https://github.com/DRincs-Productions/pixi-vn/blob/5bb5bb1f92e38998ea2f477b600168d8da3ece19/src/history/interfaces/HistoryManagerInterface.ts#L142) Map that contains all information about the steps in the history. **Don't edit unless you're sure what you're doing.** ## Methods [#methods] ### add() [#add] \> **add**(`historyInfo?`, `opstions?`): `Promise`\<`void`> Defined in: [src/history/interfaces/HistoryManagerInterface.ts:98](https://github.com/DRincs-Productions/pixi-vn/blob/5bb5bb1f92e38998ea2f477b600168d8da3ece19/src/history/interfaces/HistoryManagerInterface.ts#L98) Add a step to the history. #### Parameters [#parameters-1] ##### historyInfo? [#historyinfo] `HistoryInfo` Info about the step to add. ##### opstions? [#opstions] Options to add the step. ###### ignoreSameStep? [#ignoresamestep] `boolean` If true, the step will not be added to the history if the current step is the same as the last step. #### Returns [#returns-4] `Promise`\<`void`> *** ### blockGoBack() [#blockgoback] \> **blockGoBack**(): `void` Defined in: [src/history/interfaces/HistoryManagerInterface.ts:85](https://github.com/DRincs-Productions/pixi-vn/blob/5bb5bb1f92e38998ea2f477b600168d8da3ece19/src/history/interfaces/HistoryManagerInterface.ts#L85) Block the go back function. #### Returns [#returns-5] `void` *** ### clear() [#clear] \> **clear**(): `void` Defined in: [src/history/interfaces/HistoryManagerInterface.ts:110](https://github.com/DRincs-Productions/pixi-vn/blob/5bb5bb1f92e38998ea2f477b600168d8da3ece19/src/history/interfaces/HistoryManagerInterface.ts#L110) Clear the history. #### Returns [#returns-6] `void` *** ### delete() [#delete] \> **delete**(`stepIndex`): `void` Defined in: [src/history/interfaces/HistoryManagerInterface.ts:136](https://github.com/DRincs-Productions/pixi-vn/blob/5bb5bb1f92e38998ea2f477b600168d8da3ece19/src/history/interfaces/HistoryManagerInterface.ts#L136) Remove a step from the history. #### Parameters [#parameters-2] ##### stepIndex [#stepindex] `number` The key (id) of the step to remove. #### Returns [#returns-7] `void` True if the step was removed, false if it was not found. *** ### export() [#export] \> **export**(): `Promise`\<[`HistoryGameState`](/pixi-vn/index/interfaces/HistoryGameState)> Defined in: [src/history/interfaces/HistoryManagerInterface.ts:163](https://github.com/DRincs-Productions/pixi-vn/blob/5bb5bb1f92e38998ea2f477b600168d8da3ece19/src/history/interfaces/HistoryManagerInterface.ts#L163) Export the history to an object. #### Returns [#returns-8] `Promise`\<[`HistoryGameState`](/pixi-vn/index/interfaces/HistoryGameState)> The history in an object. *** ### get() [#get] \> **get**(`stepIndex`): [`NarrationHistory`](/pixi-vn/index/interfaces/NarrationHistory) | `undefined` Defined in: [src/history/interfaces/HistoryManagerInterface.ts:130](https://github.com/DRincs-Productions/pixi-vn/blob/5bb5bb1f92e38998ea2f477b600168d8da3ece19/src/history/interfaces/HistoryManagerInterface.ts#L130) Get a step from the history. **Note:** If the step not contains any information, this method will return undefined. #### Parameters [#parameters-3] ##### stepIndex [#stepindex-1] `number` The key (id) of the step to get. #### Returns [#returns-9] [`NarrationHistory`](/pixi-vn/index/interfaces/NarrationHistory) | `undefined` The step. *** ### keys() [#keys] \> **keys**(): `MapIterator`\<`number`> Defined in: [src/history/interfaces/HistoryManagerInterface.ts:122](https://github.com/DRincs-Productions/pixi-vn/blob/5bb5bb1f92e38998ea2f477b600168d8da3ece19/src/history/interfaces/HistoryManagerInterface.ts#L122) Get all the keys (id) of the history. #### Returns [#returns-10] `MapIterator`\<`number`> *** ### removeNarrativeHistory() [#removenarrativehistory] \> **removeNarrativeHistory**(`itemsNumber?`): `void` Defined in: [src/history/interfaces/HistoryManagerInterface.ts:66](https://github.com/DRincs-Productions/pixi-vn/blob/5bb5bb1f92e38998ea2f477b600168d8da3ece19/src/history/interfaces/HistoryManagerInterface.ts#L66) Delete the narrative history. #### Parameters [#parameters-4] ##### itemsNumber? [#itemsnumber] `number` The number of items to delete. If undefined, all items will be deleted. #### Returns [#returns-11] `void` *** ### restore() [#restore] \> **restore**(`data`): `Promise`\<`void`> Defined in: [src/history/interfaces/HistoryManagerInterface.ts:168](https://github.com/DRincs-Productions/pixi-vn/blob/5bb5bb1f92e38998ea2f477b600168d8da3ece19/src/history/interfaces/HistoryManagerInterface.ts#L168) Restore the history from an object. #### Parameters [#parameters-5] ##### data [#data] `object` The history in an object. #### Returns [#returns-12] `Promise`\<`void`>