partial.lenses: query array by sub array object property

partial.lenses-query-array-by-sub-array-object-property

// REPL: https://calmm-js.github.io/partial.lenses/playground.html
// discussion: https://gitter.im/calmm-js/chat?at=58ecf9c6bdf4acc1124c504f
const list = 
  {
    tasks: [ { id: 2
             , state: 'todo'
             , users: [ { id: 1 } ]
             }
           , { id: 2
             , state: 'todo'
             , users: [ { id: 1 }
                      , { id: 5 }
                      ]
             }
           , { id: 4
             , state: 'todo'
             , users: [ { id: 2 } ] 
             }
           ]
  }

const hasUserWithID = id => 
 L.when( L.any( R.equals( id )
              , [ 'users'
                , L.elems
                , 'id'
                ]
              )
       )

const tasksForUser = id =>
  [ 'tasks'
  , L.elems
  , hasUserWithID( id )
  ]
  
// return an array of tasks having user.id === 1
L.collect( tasksForUser( 1 ), list )
// set task.state to 'audit' on all tasks having user.id === 1
L.set( [ tasksForUser( 1 ), 'state' ], 'audit', list )

// partial.lenses: // REPL: https://calmm-js.github.io/partial.lenses
// calmm-js: https://github.com/calmm-js