kdel

Uses one or more keys to locate and delete a value in a Map, Object, or other collection. Supports nesting, loose key matching, recursive deletion, and more.

Installation

Requires Node.js 8.3.0 or above.

npm i kdel

API

The module exports a del() function that has one other function attached to it as a method: del.all().

del()

Parameters

1. Bindable: obj (Array, Iterator, Map, Object, Set, or Typed Array): The key-value collection with the value to be deleted.
2. keychain (any, or array of any): The key at which the value to be deleted is located, or an array of nested keys.
3. Optional: Object argument:
   • arrays / maps / sets / weakMaps (arrays of classes/strings): Arrays of classes and/or string names of classes that should be treated as equivalent to Array/Map/Set/WeakMap (respectively).
   • delete (function): A callback which, if provided, will override the built-in code that removes a key from a collection. Use this if you need to support collections whose custom APIs preclude the use of parameters like maps. The callback will be called with four arguments: the collection, the key, the options object, and a callback for the built-in deletion behavior (to which your custom delete callback can defer if it determines that it doesn’t need to override the default behavior after all).
   • elseThrow (Error or string): An error to be thrown if keychain references nested collections that do not exist. A string will be wrapped in an Error object automatically.
   • get (function): A callback which, if provided, will override the built-in code that fetches a key from a collection. Use this if you need to support custom classes, for example. The callback will be called with five arguments: the collection, the key, the options object, the fallback to return if the key is not found, and a callback for the built-in get behavior (to which your custom get callback can defer if it determines that it doesn’t need to override the default behavior after all).
   • isEmpty (function): A callback which, if provided, will override the built-in code that checks whether a collection is empty. Use this if you need to support collections whose custom APIs preclude the use of parameters like maps. The callback will be called with three arguments: the collection, the options object, and a callback for the built-in behavior (to which your custom isEmpty callback can defer if it determines that it doesn’t need to override the default behavior after all).
   • loose (boolean): Whether or not to evaluate keys loosely (as defined by looselyEquals). Defaults to false.
   • looselyEquals (function): A callback that accepts two values and returns true if they are to be considered equivalent or false otherwise. This argument is only used if loose is true. If omitted, the default behavior will, among other things, consider arrays/objects to be equal if they have the same entries.
   • preferStrict (boolean): Only applies if loose is true. If true, then strictly-identical keys will be preferred over loosely-equivalent keys. Otherwise, the first loosely-equivalent key found will be used, even if a strictly-identical one comes later. Defaults to false.
   • recursive (boolean): Whether or not to delete empty ancestors in keychain. Defaults to false.

Return Value

Returns true if the entire keychain existed and the deletion was successful; otherwise false.

Even if the function returns false due to part of the keychain not existing, those keys that did exist will have been deleted if recursive was set to true.

Examples

Maps

const del = require('kdel')

const map = new Map([['key', 'value']])
map.has('key') // true

del(map, 'key') // true
map.has('key') // false

del(map, 'not a key') // false

Objects

const del = require('kdel')

const obj = {key1: {key2a: 'a', key2b: 'b'}}
obj.key1.key2a // 'a'
obj.key1.key2b // 'b'

del(obj, ['key1', 'key2a']) // true
obj.key1.key2a // undefined
obj.key1.key2b // 'b'

del(obj, ['key1', 'key2b'], {recursive: true}) // true
obj.key1 // undefined

del.all()

Use this method if you want to delete multiple keys at once.

Parameters

The parameters are the same as the main function, except that the second parameter is called keychains and accepts an array of keychain arguments.

Return Value

An array of booleans, one for each keychain. Each boolean indicates whether the corresponding keychain was found and the deletion was successful.

Example

const del = require('kdel')

const obj = {a: {b1: 1, b2: 2}}
del.all(obj, [['a', 'b1'], 'c']) // [true, false]

obj.a.b1 // undefined
obj.a.b2 // 2

Related

The “k” family of modules works on keyed/indexed collections.

• khas
• kget
• kedit
• kset
• kinc

The “v” family of modules works on any collection of values.

• vhas
• vget
• vsize
• vadd
• vdel