Bunny Utils

This repository was created to write various interesting functions/classes to improve my hard skills. So far, this will be a collection of little-related things. To write them, I use different ideas from different libraries (I will add links to the libraries that inspired me) and write my own implementations based on them.

Stringify

Implementation of JSON.stringify.

Features:

• symbol supports
• cycle reference save
• stable key order for deterministic result (except symbols because they may have same names)
• well configurable indent
• more functionality replacer

API

API

example:

const stringify = require('bunny-utils').stringify;

const result = stringify({b: 123, a: {}}, {newLine: true, indend: 2, keyValueIndent: 1});
/*

{
  "a": {},
  "b": 123
}

*/

stringify() takes two parameters: value to stringify and options. Options are optionals. Result always is a string unlike JSON.stringify() can return undefined. Value is any. Options should be an object with optional properties:

• replacer - function, default null. This function will be called for every value during stringify recursively. Should return an object with properties key and value that will be used as new key and value for stringify. If there is an array - key will be null and returning key will be ignored. Default is null
• comparator - boolean or function, default true. In case if boolean: true - use default comparator that use localeCompare of string, false - don't use comparison. If function - it will be passed as callback to Array.sort(), so it takes two arguments string or symbol and return number. If number > 0 - first element after second, if number < 0 - second element after first, if number = 0 - ignore element order
• newLine - boolean, default false. If true - pretty json with line breaks
• indent - number, default 0. Specify indent for every new nesting level
• keyValueIndent - number, default 0. Specify indent between key and value. For example common pretty json has 1
• ignoreCycles - boolean, default true. If true - every cycle will be replaced with string "__cycle__" if false - throw error for first cycle. Consider that for avoiding infinite loop we mast track cycles, so set this option to false doesn't increase performance
• ignoreSymbols - boolean, default false. If false - also stringify symbols by using symbol.toString(). If true - ignore symbol keys

Inspired libraries:

• https://github.com/ljharb/json-stable-stringify
• https://github.com/ljharb/jsonify
• https://github.com/BridgeAR/safe-stable-stringify

LRU Cache (in development)

Implementation of lru-cache using doubly linked list. Memory: O(n), set/get/has/delete: O(1) where n - count of elements Inspired libraries:

• https://github.com/rsms/js-lru (main idea)