ChainedMap

🗺 ChainedMap

extension of Map

• definition
• examples
  • minimal
  • diving deeper
  • sugar
• tap
• related

definition

// this is to avoid circular requires
// because MergeChain & MethodChain extend this
// yet .method & .merge use those chains
class ChainedMapBase extends Chainable {
  public meta: Meta
  public store: Map<any, any> // = new Map()

  public values(): Primitive[]
  public extend(methods: string[]): ChainAble

  // MapIterator -> `{[key]: value}`
  // with all chain properties if they exist
  public entries(reduceInstanceProperties: boolean): Obj

  public from(obj: Obj): ChainAble
  public tap(name: Primitive, fn: FnTap): ChainAble

  public get(name: Primitive): Primitive
  public set(name: Primitive, value: Primitive): ChainAble
}

interface MergeFn extends FunctionWithSingleArg {
  (merger: MergeChain): any
}

class ChainedMap extends ChainedMapBase {
  public method(names: strings): MethodChain
  public methods(names: strings): MethodChain
  public merge(objToMerge: Obj, fn?: MergeFn): ChainAble
}

📘 examples

👾 minimal

exactly the same as using Map

const ChainedMap = require('chain-able/ChainedMap')

const chain = new ChainedMap()

chain.set('canada', '🇨🇦')
chain.has('canada') === true
chain.get('canada') === '🇨🇦'

chain.delete('canada')
chain.has('canada') === false

🏊 diving deeper

class Chained extends Chainable {
  constructor(parent) {
    super(parent)
    this.extend(['eh', 'canada'])
  }
}

// doing the above is the same as
class Chained extends Chainable {
  eh(arg) {
    return this.set('eh', arg)
  }
  canada(arg) {
    return this.set('canada', arg)
  }
}

🍬 sugar

const {canada} = new ChainedMap()
  .extend(['eh'])
  .eh('eh!')
  .merge({canada: true})
  .tap('canada', canada => '🇨🇦')
  .setIfEmpty('ooo', 'ahh')
  .entries()

tap

👆 tap a value with a function

new Chain()
  .set('eh', 'eh')
  .tap('eh', x => x + '!')
  .get('eh') === 'eh!'

this replaced the previous .concat and .append in this simple example, when the existing value for key is an array or a string, append val to it

const {str, arr} = new Chain()
  .set('str', 'emptyish')
  .tap('str', str => str + '+')
  .set('arr', [1])
  .tap('arr', arr => arr.concat([2]))
  .entries()

str == 'emptyish+'
arr == [1, 2]

🔗 related

• code
• Map
• most tests & classes extend + use ChainedMap as the core