DeprecationWarning: Buffer() is deprecated due to security and usability issues

# Table of Contents

1. DeprecationWarning: Buffer() is deprecated due to security and usability issues
2. Creating a Buffer that contains a string
3. Creating a Buffer of a desired length
4. Creating a Buffer from an array of bytes

# DeprecationWarning: Buffer() is deprecated due to security and usability issues

The message "DeprecationWarning: Buffer() is deprecated due to security and usability issues" is shown because the Buffer() constructor has been deprecated.

To resolve the issue, use one of the Buffer.from(), Buffer.aloc() and Buffer.allocUnsafe() methods.

Here is an example of how the warning is shown.

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// ⛔️ Deprecated code
const buf = new Buffer('bobbyhadz.com', 'utf8');
console.log(buf);

Running the code produces the following output.

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(node:1391456) [DEP0005] DeprecationWarning: Buffer() is deprecated due to security and usability issues. Please use the Buffer.alloc(), Buffer.allocUnsafe(), or Buffer.from() methods instead.

(Use `node --trace-deprecation ...` to show where the warning was created)

If you use VS Code, you might also see the following message:

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The signature '(str: string, encoding?: BufferEncoding | undefined): Buffer' of 'Buffer' is deprecated.ts(6387)

buffer.d.ts(234, 16): The declaration was marked as deprecated here.

# Creating a Buffer that contains a string

The issue in the following deprecated code:

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// ⛔️ Deprecated code
const buf = new Buffer('bobbyhadz.com', 'utf8');
console.log(buf);

Can be resolved using the Buffer.from() method.

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// ✅ Correct code
const buf = Buffer.from('bobbyhadz.com', 'utf8');
console.log(buf);

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// ⛔️ Before (deprecated)

const buf = new Buffer(string);

// ------------------------------

// ✅ After (correct)

const buf = Buffer.from(string)

Specifying the encoding as the second argument to the Buffer.from() method is optional.

If you don't specify the encoding, it defaults to utf8.

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const buf = Buffer.from('bobbyhadz.com');

// 👇️ <Buffer 62 6f 62 62 79 68 61 64 7a 2e 63 6f 6d>
console.log(buf);

# Creating a Buffer of a desired length

If you pass a number (size) to the Buffer() constructor, use the Buffer.alloc() method instead.

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// ⛔️ before (deprecated)

const buf = new Buffer(number);

// ------------------------------

// ✅ after (correct)

const buf = Buffer.alloc(number)

For example, the issue in the following deprecated code:

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// ⛔️ Deprecated code
const buf = new Buffer(1234);
console.log(buf);

Can be resolved using the Buffer.alloc() method.

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// ✅ Correct code
const buf = Buffer.alloc(1234);
console.log(buf);

The buffer.alloc() method can be passed the size as the first argument (the desired length of the new Buffer).

The method allocates a new Buffer of the specified size bytes.

# Creating a Buffer from an array of bytes

You might also have to create a Buffer from an array of bytes in the range 0 - 255.

For example, the issue in the following deprecated code:

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// ⛔️ Deprecated code
const arr = [0x62, 0x75, 0x66, 0x66, 0x65, 0x72];

const buf = new Buffer(arr);
console.log(buf);

Can be resolved using the Buffer.from() method.

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const arr = [0x62, 0x75, 0x66, 0x66, 0x65, 0x72];

const buf = Buffer.from(arr);

// 👇️ <Buffer 62 75 66 66 65 72>
console.log(buf);

The Buffer.from(array) method allocates a new Buffer using an array of bytes in the range 0 - 255.

# Conclusion

The deprecated new Buffer() constructor should be replaced with one of the following 3 methods:

• Buffer.from()
• Buffer.alloc()
• Buffer.allocUnsafe()

# Additional Resources

You can learn more about the related topics by checking out the following tutorials:

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