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Javascript – How to loop through a nested object and delete objects where values of keys match

How do I loop through a nested object of the form

{
  'AAA': 
   { oldName: { index: 0, first: 'Bob', last: 'Hanson' },
     newName: { index: 0, first: 'Bob', last: 'Hanson' }
   }, 
  'BBB': 
   { oldName: { index: 1, first: 'Velma', last: 'Jones' },
     newName: { index: 2, first: 'Velma', last: 'Roberts'} 
   },
  'CCC': 
   { oldName: { index: 2, first: 'Jou', last: 'Xi' },
     newName: { index: 3, first: 'Jou', last: 'Xi' } 
   },
  'DDD': 
   { oldName: { index: 3, first: 'Betty', last: 'Ford' },
     newName: undefined},
  'EEE': 
   { oldName: undefined,
     newName: { index: 1, first: 'Fred', last: 'Tree' } 
  } 
}

and delete all the nested objects where for each first level key AAA, BBB, CCC, DDD, EEE
the value of the key oldName = the value of key newName

So, I end up with

{
 'BBB': 
   { oldName: { index: 1, first: 'Velma', last: 'Jones' },
     newName: { index: 2, first: 'Velma', last: 'Roberts' } 
   },
  'DDD': 
   { oldName: { index: 3, first: 'Betty', last: 'Ford' },
     newName: undefined },
  'EEE': 
   { oldName: undefined,
     newName: { index: 1, first: 'Fred', last: 'Tree' } 
   } 
}
Tags:

3

Answers


  1. 0

    You can just filter the entries in data based on whether the first and last name fields are the same:

    const data = {
  'AAA': 
   { oldName: { index: 0, first: 'Bob', last: 'Hanson' },
     newName: { index: 0, first: 'Bob', last: 'Hanson' }
   }, 
  'BBB': 
   { oldName: { index: 1, first: 'Velma', last: 'Jones' },
     newName: { index: 2, first: 'Velma', last: 'Roberts'} 
   },
  'CCC': 
   { oldName: { index: 2, first: 'Jou', last: 'Xi' },
     newName: { index: 3, first: 'Jou', last: 'Xi' } 
   },
  'DDD': 
   { oldName: { index: 3, first: 'Betty', last: 'Ford' },
     newName: undefined},
  'EEE': 
   { oldName: undefined,
     newName: { index: 1, first: 'Fred', last: 'Tree' } 
  } 
}

const result = Object.fromEntries(
  Object.entries(data)
    .filter(([_, v]) => v.oldName?.first != v.newName?.first || v.oldName?.last != v.newName?.last)
)

console.log(result)
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  2. 0

    Just loop through the keys and delete when the full name hasn’t changed:

    const data = {
  'AAA': 
   { oldName: { index: 0, first: 'Bob', last: 'Hanson' },
     newName: { index: 0, first: 'Bob', last: 'Hanson' }
   }, 
  'BBB': 
   { oldName: { index: 1, first: 'Velma', last: 'Jones' },
     newName: { index: 2, first: 'Velma', last: 'Roberts'} 
   },
  'CCC': 
   { oldName: { index: 2, first: 'Jou', last: 'Xi' },
     newName: { index: 3, first: 'Jou', last: 'Xi' } 
   },
  'DDD': 
   { oldName: { index: 3, first: 'Betty', last: 'Ford' },
     newName: undefined},
  'EEE': 
   { oldName: undefined,
     newName: { index: 1, first: 'Fred', last: 'Tree' } 
  } 
}

for (const key in data) {
  const {oldName: a, newName: b} = data[key];
  a?.first === b?.first && a?.last === b?.last && delete data[key];
}

console.log(data);
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  3. 0

    use the for (const key in data) {} to get each rows and them compare the row data

    const data = {
    'AAA': 
     { oldName: { index: 0, first: 'Bob', last: 'Hanson' },
       newName: { index: 0, first: 'Bob', last: 'Hanson' }
     }, 
    'BBB': 
     { oldName: { index: 1, first: 'Velma', last: 'Jones' },
       newName: { index: 2, first: 'Velma', last: 'Roberts'} 
     },
    'CCC': 
     { oldName: { index: 2, first: 'Jou', last: 'Xi' },
       newName: { index: 3, first: 'Jou', last: 'Xi' } 
     },
    'DDD': 
     { oldName: { index: 3, first: 'Betty', last: 'Ford' },
       newName: undefined},
    'EEE': 
     { oldName: undefined,
       newName: { index: 1, first: 'Fred', last: 'Tree' } 
    } 
  }
  


for (const key in data) {
    const {oldName, newName} = data[key];
    oldName?.first === newName?.first && oldName?.last === newName?.last && delete data[key];
}
  
console.log(data);
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