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export default class EventEmitter
{
constructor()
{
this.callbacks = {}
this.callbacks.base = {}
}
on(_names, callback)
{
// Errors
if(typeof _names === 'undefined' || _names === '')
{
console.warn('wrong names')
return false
}
if(typeof callback === 'undefined')
{
console.warn('wrong callback')
return false
}
// Resolve names
const names = this.resolveNames(_names)
// Each name
names.forEach((_name) =>
{
// Resolve name
const name = this.resolveName(_name)
// Create namespace if not exist
if(!(this.callbacks[ name.namespace ] instanceof Object))
this.callbacks[ name.namespace ] = {}
// Create callback if not exist
if(!(this.callbacks[ name.namespace ][ name.value ] instanceof Array))
this.callbacks[ name.namespace ][ name.value ] = []
// Add callback
this.callbacks[ name.namespace ][ name.value ].push(callback)
})
return this
}
off(_names)
{
// Errors
if(typeof _names === 'undefined' || _names === '')
{
console.warn('wrong name')
return false
}
// Resolve names
const names = this.resolveNames(_names)
// Each name
names.forEach((_name) =>
{
// Resolve name
const name = this.resolveName(_name)
// Remove namespace
if(name.namespace !== 'base' && name.value === '')
{
delete this.callbacks[ name.namespace ]
}
// Remove specific callback in namespace
else
{
// Default
if(name.namespace === 'base')
{
// Try to remove from each namespace
for(const namespace in this.callbacks)
{
if(this.callbacks[ namespace ] instanceof Object && this.callbacks[ namespace ][ name.value ] instanceof Array)
{
delete this.callbacks[ namespace ][ name.value ]
// Remove namespace if empty
if(Object.keys(this.callbacks[ namespace ]).length === 0)
delete this.callbacks[ namespace ]
}
}
}
// Specified namespace
else if(this.callbacks[ name.namespace ] instanceof Object && this.callbacks[ name.namespace ][ name.value ] instanceof Array)
{
delete this.callbacks[ name.namespace ][ name.value ]
// Remove namespace if empty
if(Object.keys(this.callbacks[ name.namespace ]).length === 0)
delete this.callbacks[ name.namespace ]
}
}
})
return this
}
trigger(_name, _args)
{
// Errors
if(typeof _name === 'undefined' || _name === '')
{
console.warn('wrong name')
return false
}
let finalResult = null
let result = null
// Default args
const args = !(_args instanceof Array) ? [] : _args
// Resolve names (should on have one event)
let name = this.resolveNames(_name)
// Resolve name
name = this.resolveName(name[ 0 ])
// Default namespace
if(name.namespace === 'base')
{
// Try to find callback in each namespace
for(const namespace in this.callbacks)
{
if(this.callbacks[ namespace ] instanceof Object && this.callbacks[ namespace ][ name.value ] instanceof Array)
{
this.callbacks[ namespace ][ name.value ].forEach(function(callback)
{
result = callback.apply(this, args)
if(typeof finalResult === 'undefined')
{
finalResult = result
}
})
}
}
}
// Specified namespace
else if(this.callbacks[ name.namespace ] instanceof Object)
{
if(name.value === '')
{
console.warn('wrong name')
return this
}
this.callbacks[ name.namespace ][ name.value ].forEach(function(callback)
{
result = callback.apply(this, args)
if(typeof finalResult === 'undefined')
finalResult = result
})
}
return finalResult
}
resolveNames(_names)
{
let names = _names
names = names.replace(/[^a-zA-Z0-9 ,/.]/g, '')
names = names.replace(/[,/]+/g, ' ')
names = names.split(' ')
return names
}
resolveName(name)
{
const newName = {}
const parts = name.split('.')
newName.original = name
newName.value = parts[ 0 ]
newName.namespace = 'base' // Base namespace
// Specified namespace
if(parts.length > 1 && parts[ 1 ] !== '')
{
newName.namespace = parts[ 1 ]
}
return newName
}
}
@chuckntaylor
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chuckntaylor commented Nov 16, 2021

For anyone following Bruno's course and using Typescript, here is my adaptation.

interface Name {
  original: string
  value: string
  namespace: string
}

export class EventEmitter {
  callbacks: any = {}

  constructor() {
    this.callbacks = {}
    this.callbacks.base = {}
  }

  on(_names: string, callback: Function) {
    // Errors
    if (typeof _names === 'undefined' || _names === '') {
      console.warn('wrong names')
      return false
    }

    if (typeof callback === 'undefined') {
      console.warn('wrong callback')
      return false
    }

    // Resolve names
    const names = this.resolveNames(_names)

    // Each name
    names.forEach((_name) => {
      // Resolve name
      const name = this.resolveName(_name)

      // Create namespace if not exist
      if (!(this.callbacks[name.namespace] instanceof Object)) this.callbacks[name.namespace] = {}

      // Create callback if not exist
      if (!(this.callbacks[name.namespace][name.value] instanceof Array))
        this.callbacks[name.namespace][name.value] = []

      // Add callback
      this.callbacks[name.namespace][name.value].push(callback)
    })

    return this
  }

  off(_names: string) {
    // Errors
    if (typeof _names === 'undefined' || _names === '') {
      console.warn('wrong name')
      return false
    }

    // Resolve names
    const names = this.resolveNames(_names)

    // Each name
    names.forEach((_name) => {
      // Resolve name
      const name = this.resolveName(_name)

      // Remove namespace
      if (name.namespace !== 'base' && name.value === '') {
        delete this.callbacks[name.namespace]
      }

      // Remove specific callback in namespace
      else {
        // Default
        if (name.namespace === 'base') {
          // Try to remove from each namespace
          for (const namespace in this.callbacks) {
            if (
              this.callbacks[namespace] instanceof Object &&
              this.callbacks[namespace][name.value] instanceof Array
            ) {
              delete this.callbacks[namespace][name.value]

              // Remove namespace if empty
              if (Object.keys(this.callbacks[namespace]).length === 0) delete this.callbacks[namespace]
            }
          }
        }

        // Specified namespace
        else if (
          this.callbacks[name.namespace] instanceof Object &&
          this.callbacks[name.namespace][name.value] instanceof Array
        ) {
          delete this.callbacks[name.namespace][name.value]

          // Remove namespace if empty
          if (Object.keys(this.callbacks[name.namespace]).length === 0) delete this.callbacks[name.namespace]
        }
      }
    })

    return this
  }

  trigger(_name: string, _args?: any[]) {
    // Errors
    if (typeof _name === 'undefined' || _name === '') {
      console.warn('wrong name')
      return false
    }

    let finalResult: any = null
    let result = null

    // Default args
    const args = !(_args instanceof Array) ? [] : _args

    // Resolve names (should on have one event)
    let nameArray = this.resolveNames(_name)

    // Resolve name
    let name = this.resolveName(nameArray[0])

    // Default namespace
    if (name.namespace === 'base') {
      // Try to find callback in each namespace
      for (const namespace in this.callbacks) {
        if (
          this.callbacks[namespace] instanceof Object &&
          this.callbacks[namespace][name.value] instanceof Array
        ) {
          this.callbacks[namespace][name.value].forEach((callback: Function) => {
            result = callback.apply(this, args)

            if (typeof finalResult === 'undefined') {
              finalResult = result
            }
          })
        }
      }
    }

    // Specified namespace
    else if (this.callbacks[name.namespace] instanceof Object) {
      if (name.value === '') {
        console.warn('wrong name')
        return this
      }

      this.callbacks[name.namespace][name.value].forEach((callback: Function) => {
        result = callback.apply(this, args)

        if (typeof finalResult === 'undefined') finalResult = result
      })
    }

    return finalResult
  }

  resolveNames(_names: string) {
    let names: string | string[] = _names
    names = names.replace(/[^a-zA-Z0-9 ,/.]/g, '')
    names = names.replace(/[,/]+/g, ' ')
    names = names.split(' ')

    return names
  }

  resolveName(name: string) {
    const newName: Partial<Name> = {}
    const parts = name.split('.')

    newName.original = name
    newName.value = parts[0]
    newName.namespace = 'base' // Base namespace

    // Specified namespace
    if (parts.length > 1 && parts[1] !== '') {
      newName.namespace = parts[1]
    }

    return newName as Name
  }
}

@Beygs
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Beygs commented Sep 6, 2022

Thanks @chuckntaylor you're a legend

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