gdmn-utils

gdmn-utils

A collection of utility functions.

Functions for encoding and decoding data in base64 and UTF-8 formats

1. uint8ArrayToBase64

function uint8ArrayToBase64(uint8Array: Uint8Array): string

Description:

Converts a Uint8Array into a Base64-encoded string. This function checks for the availability of encoding methods in the environment and uses them accordingly.

Parameters:

• uint8Array (Uint8Array): The input array of 8-bit unsigned integers to be encoded.

Returns:

• string: The Base64-encoded representation of the input array.

Usage Example:

const data = new Uint8Array([72, 101, 108, 108, 111]); // Represents 'Hello'
const base64String = uint8ArrayToBase64(data);
console.log(base64String); // Outputs: 'SGVsbG8='

Notes:

• In browser environments, it uses btoa for encoding.
• In Node.js environments, it utilizes Buffer.
• Throws an error if the environment does not support Base64 encoding.

2. base64ToUint8Array

function base64ToUint8Array(base64String: string): Uint8Array

Description:

Decodes a Base64-encoded string back into a Uint8Array. The function adapts to the environment to use the appropriate decoding method.

Parameters:

• base64String (string): The Base64-encoded string to be decoded.

Returns:

• Uint8Array: The decoded array of 8-bit unsigned integers.

Usage Example:

const base64String = 'SGVsbG8=';
const data = base64ToUint8Array(base64String);
console.log(data); // Outputs: Uint8Array(5) [72, 101, 108, 108, 111]

Notes:

• In Node.js environments, it uses Buffer for decoding.
• In browser environments, it utilizes atob.
• Throws an error if the environment does not support Base64 decoding.

3. uint8ArrayToUtf8String

function uint8ArrayToUtf8String(uint8Array: Uint8Array): string

Description:

Converts a Uint8Array into a UTF-8 encoded string using the TextDecoder API.

Parameters:

• uint8Array (Uint8Array): The input array of 8-bit unsigned integers to be converted.

Returns:

• string: The resulting UTF-8 string.

Usage Example:

const data = new Uint8Array([72, 101, 108, 108, 111]);
const utf8String = uint8ArrayToUtf8String(data);
console.log(utf8String); // Outputs: 'Hello'

Notes:

• Relies on the TextDecoder API, which is widely supported in modern environments.

4. numberToUint8Array32

function numberToUint8Array32(number: number): Uint8Array

Description:

Encodes a 32-bit floating-point number into a Uint8Array. This is useful for binary data manipulation where numerical values need to be represented as byte arrays.

Parameters:

• number (number): The 32-bit floating-point number to be encoded.

Returns:

• Uint8Array: A 4-byte array representing the encoded number.

Usage Example:

const num = 3.14;
const byteArray = numberToUint8Array32(num);
console.log(byteArray); // Outputs: Uint8Array(4) [...]

Notes:

• Uses ArrayBuffer and DataView for precise byte-level manipulation.
• Assumes little-endian byte order for encoding.

5. uint8ArrayToNumber32

function uint8ArrayToNumber32(uint8Array: Uint8Array): number

Description:

Decodes a Uint8Array back into a 32-bit floating-point number. This function is the inverse of numberToUint8Array32.

Parameters:

• uint8Array (Uint8Array): A 4-byte array representing the encoded number.

Returns:

• number: The decoded 32-bit floating-point number.

Usage Example:

const byteArray = new Uint8Array([195, 245, 72, 64]);
const num = uint8ArrayToNumber32(byteArray);
console.log(num); // Outputs: 3.14

Notes:

• Assumes the input Uint8Array has a length of at least 4 bytes.
• Assumes little-endian byte order for decoding.

Environment Compatibility

• The functions uint8ArrayToBase64 and base64ToUint8Array handle both browser and Node.js environments by checking for the presence of btoa, atob, and Buffer.
• The TextDecoder API used in uint8ArrayToUtf8String is supported in modern browsers and Node.js versions.

Error Handling

• Functions uint8ArrayToBase64 and base64ToUint8Array throw an error if the environment lacks support for the necessary encoding or decoding functions.

slim

Creates a cleaned copy of an object by removing values and/or fields based on options.

Supported stripFields formats

• "field" — strip this field name at all nesting levels.
• ".field" — strip this field only at the root level.
• ".a.b.c" — strip c only when parent path is exactly a.b from root.
• ".a.*.c" — * matches one nesting step (each object key or each array item).

Wildcard example

const source = {
	attributes: {
		first: { required: true, keep: 'A' },
		second: { required: false, keep: 'B' }
	}
};

const result = slim(source, {
	deep: true,
	stripFields: ['.attributes.*.required']
});

// result:
// {
//   attributes: {
//     first: { keep: 'A' },
//     second: { keep: 'B' }
//   }
// }

When multiple deep paths are provided (for example ['.attributes.*.required', '.attributes.*.index']), they are processed together during traversal.