javascript - ArrayBuffer to base64 encoded string

Javascript - ArrayBuffer to base64 encoded string

To convert an ArrayBuffer to a base64 encoded string in JavaScript, you can follow these steps:

Steps to Convert ArrayBuffer to Base64 Encoded String:

  1. Create ArrayBuffer: Obtain the ArrayBuffer from which you want to generate the base64 string.

  2. Convert ArrayBuffer to Uint8Array: Convert the ArrayBuffer to a Uint8Array, which represents an array of 8-bit unsigned integers.

  3. Encode Uint8Array to Base64: Use btoa() function or Buffer.from() (in Node.js) to convert the Uint8Array to a base64 encoded string.

Example Code:

// Example ArrayBuffer (replace with your actual ArrayBuffer) const arrayBuffer = new Uint8Array([65, 66, 67, 68]).buffer; // Convert ArrayBuffer to Uint8Array const uint8Array = new Uint8Array(arrayBuffer); // Convert Uint8Array to base64 encoded string const base64String = btoa(String.fromCharCode.apply(null, uint8Array)); console.log(base64String); // Output: QUJDRA==

Explanation:

  • Uint8Array: Uint8Array is used to represent binary data in the form of an array of bytes. It's suitable for converting binary data like ArrayBuffer to other formats.

  • btoa(): This function converts a string of binary data (like Uint8Array) to a base64 encoded ASCII string. It's available in browsers and can be used directly.

  • String.fromCharCode.apply(null, uint8Array): This expression converts each byte in the Uint8Array to a character and then joins them into a single string. btoa() then converts this string to base64.

Node.js Alternative (Using Buffer):

In Node.js, you can use the Buffer object for similar functionality:

const arrayBuffer = Buffer.from([65, 66, 67, 68]); const base64String = arrayBuffer.toString('base64'); console.log(base64String); // Output: QUJDRA==

Notes:

  • Ensure compatibility: btoa() is supported in modern browsers. For Node.js or older browsers, consider using Buffer (Node.js) or polyfills for btoa() and Uint8Array as needed.

  • Handling Larger ArrayBuffers: If your ArrayBuffer is large, consider chunking the conversion process to avoid memory issues.

This approach should effectively convert your ArrayBuffer to a base64 encoded string in JavaScript, suitable for transmission or storage where base64 encoding is required.

Examples

  1. JavaScript ArrayBuffer to base64 string conversion

    • Description: Convert an ArrayBuffer to a base64 encoded string in JavaScript.
    • Code:
      function arrayBufferToBase64(buffer) { const bytes = new Uint8Array(buffer); const binary = bytes.reduce((acc, byte) => acc + String.fromCharCode(byte), ''); return btoa(binary); } // Usage example: const buffer = new ArrayBuffer(8); // Example buffer const base64String = arrayBufferToBase64(buffer); console.log(base64String);

  2. JavaScript convert ArrayBuffer to base64 with FileReader

    • Description: Using FileReader to convert an ArrayBuffer to a base64 encoded string in JavaScript.
    • Code:
      function arrayBufferToBase64(buffer) { return new Promise((resolve, reject) => { const reader = new FileReader(); reader.onload = () => { const base64String = reader.result.split(',')[1]; resolve(base64String); }; reader.onerror = error => reject(error); reader.readAsDataURL(new Blob([buffer])); }); } // Usage example: const buffer = new ArrayBuffer(8); // Example buffer arrayBufferToBase64(buffer) .then(base64String => console.log(base64String)) .catch(error => console.error(error));

  3. JavaScript ArrayBuffer to base64 encoded URL

    • Description: Convert an ArrayBuffer to a base64 encoded URL in JavaScript.
    • Code:
      function arrayBufferToBase64Url(buffer) { const bytes = new Uint8Array(buffer); const binary = bytes.reduce((acc, byte) => acc + String.fromCharCode(byte), ''); const base64Url = btoa(binary).replace(/\+/g, '-').replace(/\//g, '_').replace(/=/g, ''); return base64Url; } // Usage example: const buffer = new ArrayBuffer(8); // Example buffer const base64Url = arrayBufferToBase64Url(buffer); console.log(base64Url);

  4. JavaScript convert ArrayBuffer to base64 string with MIME type

    • Description: Convert an ArrayBuffer to a base64 encoded string with a specific MIME type in JavaScript.
    • Code:
      function arrayBufferToBase64WithMimeType(buffer, mimeType) { const bytes = new Uint8Array(buffer); const binary = bytes.reduce((acc, byte) => acc + String.fromCharCode(byte), ''); const base64String = `data:${mimeType};base64,${btoa(binary)}`; return base64String; } // Usage example: const buffer = new ArrayBuffer(8); // Example buffer const mimeType = 'image/jpeg'; // Example MIME type const base64String = arrayBufferToBase64WithMimeType(buffer, mimeType); console.log(base64String);

  5. JavaScript ArrayBuffer to base64 string for binary data

    • Description: Convert an ArrayBuffer containing binary data to a base64 encoded string in JavaScript.
    • Code:
      function arrayBufferToBase64Binary(buffer) { const bytes = new Uint8Array(buffer); let binary = ''; bytes.forEach(byte => binary += String.fromCharCode(byte)); return btoa(binary); } // Usage example: const buffer = new ArrayBuffer(8); // Example buffer const base64Binary = arrayBufferToBase64Binary(buffer); console.log(base64Binary);

  6. JavaScript ArrayBuffer to base64 encoded string using TextDecoder

    • Description: Convert an ArrayBuffer to a base64 encoded string using TextDecoder in JavaScript.
    • Code:
      function arrayBufferToBase64WithTextDecoder(buffer) { const decoder = new TextDecoder('utf-8'); const text = decoder.decode(buffer); return btoa(text); } // Usage example: const buffer = new ArrayBuffer(8); // Example buffer const base64String = arrayBufferToBase64WithTextDecoder(buffer); console.log(base64String);

  7. JavaScript ArrayBuffer to base64 string conversion with padding

    • Description: Convert an ArrayBuffer to a base64 encoded string with padding in JavaScript.
    • Code:
      function arrayBufferToBase64WithPadding(buffer) { const bytes = new Uint8Array(buffer); const binary = bytes.reduce((acc, byte) => acc + String.fromCharCode(byte), ''); const base64String = btoa(binary).replace(/=/g, ''); return base64String + '=='.substring(0, (3 - buffer.byteLength % 3) % 3); } // Usage example: const buffer = new ArrayBuffer(8); // Example buffer const base64String = arrayBufferToBase64WithPadding(buffer); console.log(base64String);

  8. JavaScript ArrayBuffer to base64 string conversion with URL-safe characters

    • Description: Convert an ArrayBuffer to a base64 encoded string with URL-safe characters in JavaScript.
    • Code:
      function arrayBufferToBase64UrlSafe(buffer) { const bytes = new Uint8Array(buffer); const binary = bytes.reduce((acc, byte) => acc + String.fromCharCode(byte), ''); const base64UrlSafe = btoa(binary).replace(/\+/g, '-').replace(/\//g, '_').replace(/=/g, ''); return base64UrlSafe; } // Usage example: const buffer = new ArrayBuffer(8); // Example buffer const base64UrlSafeString = arrayBufferToBase64UrlSafe(buffer); console.log(base64UrlSafeString);

  9. JavaScript ArrayBuffer to base64 string conversion with error handling

    • Description: Convert an ArrayBuffer to a base64 encoded string with error handling in JavaScript.
    • Code:
      function arrayBufferToBase64WithErrors(buffer) { try { const bytes = new Uint8Array(buffer); const binary = bytes.reduce((acc, byte) => acc + String.fromCharCode(byte), ''); return btoa(binary); } catch (error) { console.error('Error converting ArrayBuffer to base64:', error); return null; } } // Usage example: const buffer = new ArrayBuffer(8); // Example buffer const base64String = arrayBufferToBase64WithErrors(buffer); if (base64String) { console.log(base64String); }

  10. JavaScript ArrayBuffer to base64 string conversion for large data

    • Description: Convert a large ArrayBuffer to a base64 encoded string efficiently in JavaScript.
    • Code:
      async function arrayBufferToBase64LargeData(buffer) { const blob = new Blob([buffer]); const base64String = await new Promise((resolve, reject) => { const reader = new FileReader(); reader.onload = () => resolve(reader.result.split(',')[1]); reader.onerror = error => reject(error); reader.readAsDataURL(blob); }); return base64String; } // Usage example: const buffer = new ArrayBuffer(1000000); // Example large buffer arrayBufferToBase64LargeData(buffer) .then(base64String => console.log(base64String)) .catch(error => console.error(error));

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