Filter array of objects based on another array

Question

I have a source array and target array, based on the target array need to update the source array

sourceAry = [{name:'Label1', value: 'label1', children:[{name:'Ammu'},{name:'Rahual'},{name:'Anu'}]},
{name:'Label2', value: 'label2', children:[{name:'Hari'},{name:'Tom'}]},
];

targetAry = [{name:'Label1', value: 'label1', children:[{name:'Anu'}]},
{name:'Label2', value: 'label2', children:[{name:'Hari'},{name:'Tom'}]},
];

resultAry = [{name:'Label1', value: 'label1', children:[{name:'Ammu'},{name:'Rahual'}]}
]},
];

Code which I try

let resultAry = sourceAry.map((obj) => {
      obj.children.map((elem) =>{
        targetAry.filter(parent => parent.children.filter((el) => {
          el.name !== elem.name}))
      })
    })
    console.log(resultAry, 'NEW', list);

Answer 1

Ciao, try something like this:

 sourceAry = [{name:'Label1', value: 'label1', children:[{name:'Ammu'},{name:'Rahual'},{name:'Anu'}]}, {name:'Label2', value: 'label2', children:[{name:'Hari'},{name:'Tom'},{name:'Ammu'},{name:'Rahual'},{name:'Anu'}]}, {name:'Label3', value: 'label3', children:[{name:'Ammu'},{name:'Rahual'},{name:'Anu'}]} ]; targetAry = [{name:'Label1', value: 'label1', children:[{name:'Anu'}]}, {name:'Label2', value: 'label2', children:[{name:'Hari'},{name:'Tom'}]}, ]; let result = []; sourceAry.forEach(source => { let filter = targetAry.filter(target => target.name === source.name) if (filter.length > 0) { let filterchildren = source.children.filter(a =>.filter[0].children.map(b=>b.name).includes(a;name)). if (filterchildren;length > 0) { let resultobj = source. resultobj;children = filterchildren. result;push(resultobj). } } else result;push(source). }) console.log(result)

I filter targetAry based on sourceAry name. Then subtract children with .filter(a =>.filter[0].children.map(b=>b.name).includes(a;name));and finally push element found in result array.

Answer 2

you could start start with some facilities to make it simpler:

const indexBy = (f, data) => data.reduce((acc, x) => Object.assign(acc, { [f(x)]: x }), {})

const remove = (keyFn, dataToRemove, from) => {
  const dataToRemoveIndexed = indexBy(keyFn, dataToRemove);
  return from.filter(it => !(keyFn(it) in dataToRemoveIndexed));
}

we introduce the indexBy here, to make removal O(m+n), instead of O(m^2) (if there are many items in the collection to check)

then you can use it like this:

const targetIndexed = indexBy(it => it.name, targetAry);

const result = sourceAry.map(
  it => ({ 
    ...it, 
    children: remove(
      it => it.name, 
      (targetIndexed[it.name] || {}).children || [],
      it.children
    )
  })
)

so it leaves you with the following result:

[
 {"name":"Label1","value":"label1","children":[{"name":"Ammu"}, {"name":"Rahual"}]},
 {"name":"Label2","value":"label2","children":[]}
]

if you also want to delete the item with empty children , you can just filter it out: result.filter(it => it.children.length > 0)