Creating Object Using Array Elements without overwriting Existing Keys

Issue

I trying to creating an object from an array that contains many arrays.
The array element are to be nested keys of object for each other, only if the key has not be created initially. That is, it should not overwrite key and should also maintained key index.

Example is this –

const MainArray = [
                    {
                      key: ['name', 'dog', 'feature', 'hairy'],
                      value1:1 , 
                      value2:2
                     },
                    {
                      key: ['name', 'dog', 'eye', 'brown'],
                      value1:1 , 
                      value2:2
                     }, 
                    {
                      key: ['kind', 'human', 'class', 'man', 'height', 'tall'],
                      value1:'Mike' , 
                      value2:'John'
                     }, 
                     {
                      key: ['kind', 'human', 'class', 'woman', 'hobby'],
                      value1:'Cyling' , 
                      value2:'Tennis'
                     }, 

                ]


const requiredObject = 
                     {

                      name:{
                          dog :{
                            feature:{
                                   hairy :{value1:1, value2:2}
                            },
                            eye:{
                                brown:{value1:1, value2:2}
                             }
                           }
                        },
                        kind:{
                           human:{
                              class:{
                                   man:{
                                      height:{
                                        tall:{value1:'Mike', value2:'John'}
                                      }
                                   },
                                   woman:{
                                       hobby:{value1:'Cyling', value2: 'Tennis'}
                                   } 
                                }
                            }
                         }

                     }

How can I go from MainArray to requireObject

Solution

You can use array.reduce() to build a new object by traversing key arrays using another array.reduce(). Try:

const MainArray = [
    {
      key: ['name', 'dog', 'feature', 'hairy'],
      value1:1 , 
      value2:2
     },
    {
      key: ['name', 'dog', 'eye', 'brown'],
      value1:1 , 
      value2:2
     }, 
    {
      key: ['kind', 'human', 'class', 'man', 'height', 'tall'],
      value1:'Mike' , 
      value2:'John'
     }, 
     {
      key: ['kind', 'human', 'class', 'woman', 'hobby'],
      value1:'Cyling' , 
      value2:'Tennis'
     }
];


const result = MainArray.reduce((acc, cur) => {
    let { key, ...data } = cur;
    let lastIndex = key.length - 1;

    key.reduce((obj, k, index) => {
        obj[k] = obj[k] || (index === lastIndex ? {...data}  : {});
        return obj[k];
    }, acc);

    return acc;
}, {});

console.log(result);

Answered By – mickl

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