Add a Watermark to Word Documents with JavaScript in React

Incorporating a watermark to Word documents is a simple yet impactful way to protect your content and assert ownership. Whether you're marking a draft as confidential or branding a business document, watermarks can convey essential information without distracting from your text.

In this article, you will learn how to add and customize watermarks in Word documents in a React application using Spire.Doc for JavaScript.

Add a Text Watermark to Word in React
Add an Image Watermark to Word in React

Install Spire.Doc for JavaScript

To get started with adding watermarks to Word in a React application, you can either download Spire.Doc for JavaScript from our website or install it via npm with the following command:

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npm i spire.office

The downloaded product package integrates Spire.Doc for JavaScript, Spire.XLS for JavaScript, Spire.PDF for JavaScript, and Spire.Presentation for JavaScript. To use the features of Spire.Doc for JavaScript, you need to copy the corresponding files (spire.doc.js, Spire.Doc.Wasm.zip, spire.common.js, Spire.Common.Wasm.zip, and the _framework folder) to the public folder of your project. To ensure proper text rendering, you can add relevant font files with a custom path. In the following example, the font is added to the path: public\static\font.

For more details, refer to the documentation: How to Integrate Spire.Doc for JavaScript in a React Project

Add a Text Watermark to Word in React

Spire.Doc for JavaScript provides the TextWatermark class, enabling users to create customizable text watermarks with their preferred text and font effects. Once the TextWatermark object is created, it can be applied to the entire document using the Document.Watermark property.

The steps to add a text watermark to Word in React are as follows:

Load the necessary font file and input Word document into the virtual file system (VFS).
Create a Document object using the new wasmModule.Document() method.
Load the Word file using the Document.LoadFromFile() method.
Create a TextWatermark object using the new wasmModule.TextWatermark() method.
Customize the watermark's text, font size, font name, and color using the properties under the TextWatermark object.
Apply the text watermark to the document using the Document.Watermark property.
Save the document and trigger a download.

JavaScript

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import React, { useState, useEffect } from 'react';

function App() {
  const [wasmModule, setWasmModule] = useState(null);
  // Load Spire.Doc
  useEffect(() => {
    (async () => {
      try {
        const publicUrl = process.env.PUBLIC_URL || '';
        const spireModule = await import(/* webpackIgnore: true */ `${publicUrl}/spire.doc.js`);
        const rawModule = spireModule.default || spireModule;
        window.wasmModule = typeof rawModule === 'function'
          ? await rawModule({ locateFile: p => p.endsWith('.wasm') ? `${publicUrl}/${p}` : p })
          : rawModule;
        setWasmModule(window.wasmModule);
      } catch (error) {
        console.error('Failed to load spire.doc.js WASM module:', error);
      }
    })();
  }, []);

  // Function add a text watermark
  const AddWatermark = async () => {
    const wasmModule = window.wasmModule.spiredoc;

    if (wasmModule) {
      // Load the font files into the virtual file system (VFS)
      await window.spire.FetchFileToVFS('Arial.ttf', '/Library/Fonts/', `${process.env.PUBLIC_URL}/static/font/`);

      // Specify the input file name and the output file name
      const outputFileName = "TextWatermark.docx";
      const inputFileName = 'input.docx';

      // Fetch the input file and add it to the VFS
      await window.spire.FetchFileToVFS(inputFileName, '', `${process.env.PUBLIC_URL}/static/data/`);

      // Create an instance of the Document class
      const doc = new wasmModule.Document();

      // Load the Word document
      doc.LoadFromFile(inputFileName);

      // Create a TextWatermark instance
      let txtWatermark =new wasmModule.TextWatermark();

      // Set the text for the watermark
      txtWatermark.Text = "Do Not Copy";

      // Set the font size and name for the text
      txtWatermark.FontSize = 58;
      txtWatermark.FontName = "Arial"

      // Set the color of the text
      txtWatermark.Color = wasmModule.Color.get_Blue();

      // Set the layout of the watermark to diagonal
      txtWatermark.Layout = wasmModule.WatermarkLayout.Diagonal;

      // Apply the text watermark to the document
      doc.Watermark = txtWatermark;

      // Save the document to the specified path
      doc.SaveToFile({ fileName: outputFileName, fileFormat: wasmModule.FileFormat.Docx2013 });

      // Read the generated file from VFS
      const fileArray = window.dotnetRuntime.Module.FS.readFile(outputFileName);

      // Create a Blob object from the file
      const blob = new Blob([fileArray], { type: "application/vnd.openxmlformats-officedocument.wordprocessingml.document" });

      // Create a URL for the Blob
      const url = URL.createObjectURL(blob);

      // Create an anchor element to trigger the download
      const a = document.createElement('a');
      a.href = url;
      a.download = outputFileName;
      document.body.appendChild(a);
      a.click();
      document.body.removeChild(a);
      URL.revokeObjectURL(url);

      // Clean up resources
      doc.Dispose();
    }
  };

  return (
    <div style={{ textAlign: 'center', height: '300px' }}>
      <h1>Add a Text Watermark to Word in React</h1>
      <button onClick={AddWatermark} disabled={!wasmModule}>
        Generate
      </button>
    </div>
  );
}

export default App;

Run the code to launch the React app at localhost:3000. Click "Convert", and a "Save As" window will appear, prompting you to save the output file in your chosen folder.

Run React app to add watermarks to Word

Here is a screenshot of the generated Word file that includes a text watermark:

Add a text watermark to Word in React

Add an Image Watermark to Word in React

Spire.Doc for JavaScript provides the PictrueWatermark to help configure the image resource, scaling, washout effect for image watermarks in Word. Once a PictureWatermak object is created, you can apply it to an entire document using the Document.Watermark property.

Steps to add an image watermark to a Word document in React:

Load the image file and input Word document into the virtual file system (VFS).
Create a Document object using the new wasmModule.Document() method.
Load the Word file using the Document.LoadFromFile() method.
Create a PictureWatermark object using the new wasmModule.PictureWatermark() method.
Set the image resource, scaling, and washout effect for the watermark using the methods and properties under the PictureWatermark object.
Apply the image watermark to the document using the Document.Watermark property.
Save the document and trigger a download.

JavaScript

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import React, { useState, useEffect } from 'react';

function App() {
  const [wasmModule, setWasmModule] = useState(null);
  // Load Spire.Doc
  useEffect(() => {
    (async () => {
      try {
        const publicUrl = process.env.PUBLIC_URL || '';
        const spireModule = await import(/* webpackIgnore: true */ `${publicUrl}/spire.doc.js`);
        const rawModule = spireModule.default || spireModule;
        window.wasmModule = typeof rawModule === 'function'
          ? await rawModule({ locateFile: p => p.endsWith('.wasm') ? `${publicUrl}/${p}` : p })
          : rawModule;
        setWasmModule(window.wasmModule);
      } catch (error) {
        console.error('Failed to load spire.doc.js WASM module:', error);
      }
    })();
  }, []);

  // Function add an image watermark
  const AddWatermark = async () => {
    const wasmModule = window.wasmModule.spiredoc;

    if (wasmModule) {
      // Load the font files into the virtual file system (VFS)
      await window.spire.FetchFileToVFS('Arial.ttf', '/Library/Fonts/', `${process.env.PUBLIC_URL}/static/font/`);

      // Specify the input file name and the output file name
      const outputFileName = 'ImageWatermark.docx';
      const inputFileName = 'input.docx';
      const imageFileName = 'logo.png';

      // Fetch the input file and add it to the VFS
      await window.spire.FetchFileToVFS(inputFileName, '', `${process.env.PUBLIC_URL}/static/data/`);
      await window.spire.FetchFileToVFS(imageFileName, '', `${process.env.PUBLIC_URL}/static/data/`);

      // Create an instance of the Document class
      const doc = new wasmModule.Document();

      // Load the Word document
      doc.LoadFromFile(inputFileName);

      // Create a new PictureWatermark instance
      const pictureWatermark = new wasmModule.PictureWatermark();

      // Set the picture
      pictureWatermark.SetPicture(imageFileName);

      // Set the scaling factor of the image
      pictureWatermark.Scaling = 150;

      // Disable washout effect
      pictureWatermark.IsWashout = false;

      // Apply the image watermark to the document
      doc.Watermark = pictureWatermark;

      // Save the document to the specified path
      doc.SaveToFile({ fileName: outputFileName, fileFormat: wasmModule.FileFormat.Docx2013 });

      // Read the generated file from VFS
      const fileArray = window.dotnetRuntime.Module.FS.readFile(outputFileName);

      // Create a Blob object from the file
      const blob = new Blob([fileArray], { type: "application/vnd.openxmlformats-officedocument.wordprocessingml.document" });

      // Create a URL for the Blob
      const url = URL.createObjectURL(blob);

      // Create an anchor element to trigger the download
      const a = document.createElement('a');
      a.href = url;
      a.download = outputFileName;
      document.body.appendChild(a);
      a.click();
      document.body.removeChild(a);
      URL.revokeObjectURL(url);

      // Clean up resources
      doc.Dispose();
    }
  };

  return (
    <div style={{ textAlign: 'center', height: '300px' }}>
      <h1>Add an Image Watermark to Word in React</h1>
      <button onClick={AddWatermark} disabled={!wasmModule}>
        Generate
      </button>
    </div>
  );
}

export default App;

Add an image watermark to Word in React

Get a Free License

To fully experience the capabilities of Spire.Doc for JavaScript without any evaluation limitations, you can request a free 30-day trial license.

Add a Watermark to Word Documents with JavaScript in React

Install Spire.Doc for JavaScript

Add a Text Watermark to Word in React

Add an Image Watermark to Word in React

Get a Free License

See Also