# Blob & File > Language fallback: requested `zh-CN`; content is `en-US`. - Human documentation: [https://docs.univer.ai/zh-CN/reference/facade/utils](https://docs.univer.ai/zh-CN/reference/facade/utils) - Agent Markdown: [https://docs.univer.ai/zh-CN/reference/facade/utils.md](https://docs.univer.ai/zh-CN/reference/facade/utils.md) - Requested language: `zh-CN` - Content language: `en-US` - Documentation version: `1.0.0-rc.0` - Source: [facade/utils.mdx](https://github.com/dream-num/documentation/blob/dev/content/reference/facade/utils.mdx) --- | Packages | `@univerjs/core` | | -------- | ---------------- | > This class should not be instantiated directly. Use factory methods on `univerAPI` instead. ## Overview ### @univerjs/core | Method | Description | | ----------------------------------------- | ------------------------------------------------------------------------------------ | | [`copyBlob`](#copyblob) | Returns a copy of this blob | | [`extend`](#extend) | - | | [`get`](#get) | - | | [`getAs`](#getas) | Return the data inside this object as a blob converted to the specified content type | | [`getBytes`](#getbytes) | Gets the data stored in this blob | | [`getContentType`](#getcontenttype) | Gets the content type of the data stored in this blob | | [`getDataAsString`](#getdataasstring) | - | | [`onBeforeRedo`](#onbeforeredo) | - | | [`onBeforeUndo`](#onbeforeundo) | - | | [`onReady`](#onready) | - | | [`onRedo`](#onredo) | - | | [`onRendered`](#onrendered) | - | | [`onStarting`](#onstarting) | - | | [`onSteady`](#onsteady) | - | | [`onUndo`](#onundo) | - | | [`rectangle`](#rectangle) | Access rectangle helper utilities | | [`setBytes`](#setbytes) | Sets the data stored in this blob | | [`setContentType`](#setcontenttype) | Sets the content type of the data stored in this blob | | [`setDataFromString`](#setdatafromstring) | - | | [`tools`](#tools) | Access common helper utilities | ## APIs ### Getters & Queries ### `rectangle` Access rectangle helper utilities. **Signature** ```typescript get rectangle(): typeof Rectangle ``` **Returns** * `typeof Rectangle` — Rectangle helper utilities exposed through `univerAPI.Util.rectangle`. Source: `@univerjs/core` ### `tools` Access common helper utilities. **Signature** ```typescript get tools(): typeof Tools ``` **Returns** * `typeof Tools` — Common helper utilities exposed through `univerAPI.Util.tools`. Source: `@univerjs/core` ### `get` **Signature** ```typescript static get(): FUtil ``` **Returns** * `FUtil` — See signature above. Source: `@univerjs/core` ### `getAs` Return the data inside this object as a blob converted to the specified content type. **Signature** ```typescript getAs(contentType: string): FBlob ``` **Parameters** * `contentType` `string` — *No description* **Returns** * `FBlob` — a new blob by converting the current blob to the specified content type **Examples** ```ts const blob = univerAPI.newBlob(); const newBlob = blob.getAs('text/plain'); console.log(newBlob); ``` Source: `@univerjs/core` ### `getBytes` Gets the data stored in this blob. **Signature** ```typescript getBytes(): Promise ``` **Returns** * `Promise>` — the blob content as a byte array **Examples** ```ts const blob = univerAPI.newBlob(); const bytes = await blob.getBytes(); console.log(bytes); ``` Source: `@univerjs/core` ### `getContentType` Gets the content type of the data stored in this blob. **Signature** ```typescript getContentType(): string | undefined ``` **Returns** * `string` — the content type **Examples** ```ts const blob = univerAPI.newBlob(); const contentType = blob.getContentType(); console.log(contentType); ``` Source: `@univerjs/core` ### `getDataAsString` **Signature** ```typescript getDataAsString(charset?: string): Promise ``` **Parameters** * `charset` `string` *(optional)* — *No description* **Returns** * `Promise` — See signature above. Source: `@univerjs/core` ### Setters & Modifiers ### `setBytes` Sets the data stored in this blob. **Signature** ```typescript setBytes(bytes: Uint8Array): FBlob ``` **Parameters** * `bytes` `Uint8Array` — *No description* **Returns** * `FBlob` — the blob object **Examples** ```ts const blob = univerAPI.newBlob(); const bytes = new Uint8Array(10); blob.setBytes(bytes); ``` Source: `@univerjs/core` ### `setContentType` Sets the content type of the data stored in this blob. **Signature** ```typescript setContentType(contentType: string): FBlob ``` **Parameters** * `contentType` `string` — *No description* **Returns** * `FBlob` — the blob object **Examples** ```ts const blob = univerAPI.newBlob(); blob.setContentType('text/plain'); ``` Source: `@univerjs/core` ### `setDataFromString` **Signature** ```typescript setDataFromString(data: string, contentType?: string): FBlob ``` **Parameters** * `data` `string` — *No description* * `contentType` `string` *(optional)* — *No description* **Returns** * `FBlob` — See signature above. Source: `@univerjs/core` ### Actions & Operations ### `copyBlob` Returns a copy of this blob. **Signature** ```typescript copyBlob(): FBlob ``` **Returns** * `FBlob` — a new blob by copying the current blob **Examples** ```ts const blob = univerAPI.newBlob(); const newBlob = blob.copyBlob(); console.log(newBlob); ``` Source: `@univerjs/core` ### Events ### `onBeforeRedo` > [!WARN] > Deprecated — use > > `univerAPI.addEvent(univerAPI.Event.BeforeRedo, (event) => {})` > > as instead **Signature** ```typescript onBeforeRedo(callback: (action: IUndoRedoItem) => void): IDisposable ``` **Parameters** * `callback` `(action: IUndoRedoItem) => void` — *No description* **Returns** * `IDisposable` — See signature above. Source: `@univerjs/core` ### `onBeforeUndo` > [!WARN] > Deprecated — use > > `univerAPI.addEvent(univerAPI.Event.BeforeUndo, (event) => {})` > > as instead **Signature** ```typescript onBeforeUndo(callback: (action: IUndoRedoItem) => void): IDisposable ``` **Parameters** * `callback` `(action: IUndoRedoItem) => void` — *No description* **Returns** * `IDisposable` — See signature above. Source: `@univerjs/core` ### `onReady` > [!WARN] > Deprecated — use > > `univerAPI.addEvent(univerAPI.Event.LifeCycleChanged, ({ stage }) => {})` > > as instead **Signature** ```typescript onReady(callback: () => void): IDisposable ``` **Parameters** * `callback` `() => void` — *No description* **Returns** * `IDisposable` — See signature above. Source: `@univerjs/core` ### `onRedo` > [!WARN] > Deprecated — use > > `univerAPI.addEvent(univerAPI.Event.Redo, (event) => {})` > > as instead **Signature** ```typescript onRedo(callback: (action: IUndoRedoItem) => void): IDisposable ``` **Parameters** * `callback` `(action: IUndoRedoItem) => void` — *No description* **Returns** * `IDisposable` — See signature above. Source: `@univerjs/core` ### `onRendered` > [!WARN] > Deprecated — use > > `univerAPI.addEvent(univerAPI.Event.LifeCycleChanged, ({ stage }) => {})` > > as instead **Signature** ```typescript onRendered(callback: () => void): IDisposable ``` **Parameters** * `callback` `() => void` — *No description* **Returns** * `IDisposable` — See signature above. Source: `@univerjs/core` ### `onStarting` > [!WARN] > Deprecated — use > > `univerAPI.addEvent(univerAPI.Event.LifeCycleChanged, ({ stage }) => {})` > > as instead **Signature** ```typescript onStarting(callback: () => void): IDisposable ``` **Parameters** * `callback` `() => void` — *No description* **Returns** * `IDisposable` — See signature above. Source: `@univerjs/core` ### `onSteady` > [!WARN] > Deprecated — use > > `univerAPI.addEvent(univerAPI.Event.LifeCycleChanged, ({ stage }) => {})` > > as instead **Signature** ```typescript onSteady(callback: () => void): IDisposable ``` **Parameters** * `callback` `() => void` — *No description* **Returns** * `IDisposable` — See signature above. Source: `@univerjs/core` ### `onUndo` > [!WARN] > Deprecated — use > > `univerAPI.addEvent(univerAPI.Event.Undo, (event) => {})` > > as instead **Signature** ```typescript onUndo(callback: (action: IUndoRedoItem) => void): IDisposable ``` **Parameters** * `callback` `(action: IUndoRedoItem) => void` — *No description* **Returns** * `IDisposable` — See signature above. Source: `@univerjs/core` ### Miscellaneous ### `extend` **Signature** ```typescript static extend(source: any): void ``` **Parameters** * `source` `any` — *No description* Source: `@univerjs/core`