Question 207721 in Javascript Question posted in
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Javascript – How to add a new object before found object's key value pair in nested array

The code i tried but no change in array

const data = [
  {
    name: 'Fruit',
    children: [{ name: 'Apple' }, { name: 'Banana' }, { name: 'Fruit loops' }],
  },
  {
    name: 'Vegetables',
    children: [
      {
        name: 'Green',
        children: [{ name: 'Broccoli' }, { name: 'Brussels sprouts' }],
      },
     {
        name: 'Orange',
        children: [{ name: 'Pumpkins' }, { name: 'Carrots' }],
      },
    ],
  },
];

output needed

 const data = [
   {
     name: 'Fruit',
     children: [{ name: 'Apple' }, { name: 'Banana' }, { name: 'Fruit loops' }],
   },
   {
     name: 'Vegetables',
     children: [
       {
         name: 'Green',
         children: [{ name: 'Broccoli' }, { name: 'Brussels sprouts' }],
       },
       {
         name: 'Orange',
         children: [{ name: 'Pumpkins' },{name:'newname'} { name: 'Carrots' }],
       },
     ],
   },
 ];


function addObjectBefore(arr, targetName, newObj) {
  for (let i = 0; i < arr.length; i++) {
    if (arr[i].children) {
      addObjectBefore(arr[i].children, targetName, newObj); // Recursive call for nested children array
    }
    if (arr[i].name === targetName) {
      const targetIndex = arr[i]?.children?.findIndex(obj => obj.name === targetName);
      arr[i]?.children?.splice(targetIndex, 0, newObj); // Insert new object before the target
      break; // Stop the iteration once the target is found and object is inserted
    }
  }
}

// Given data
const data = [
  {
    name: 'Fruit',
    children: [{ name: 'Apple' }, { name: 'Banana' }, { name: 'Fruit loops' }],
  },
  {
    name: 'Vegetables',
    children: [
      {
        name: 'Green',
        children: [{ name: 'Broccoli' }, { name: 'Brussels sprouts' }],
      },
      {
        name: 'Orange',
        children: [{ name: 'Pumpkins' }, { name: 'Carrots' }],
      },
    ],
  },
];

// Call the function to add the new object
addObjectBefore(data, 'Pumpkins', { name: 'new name' });

// Output the modified data
console.log(data);
Tags:

2

Answers


  1. 0 
    function addObjectBefore(arr, targetName, newObj) {
  for (let i = 0; i < arr.length; i++) {
    if (arr[i].children) {
      const targetIndex = arr[i].children.findIndex(obj => obj.name === targetName);
      if (targetIndex !== -1) {
        arr[i].children.splice(targetIndex, 0, newObj); // Insert new object before the target
        return; // Stop the iteration once the target is found and object is inserted
      } else {
        addObjectBefore(arr[i].children, targetName, newObj); // Recursive call for nested children array
      }
    }
  }
}

const data = [
  {
    name: 'Fruit',
    children: [{ name: 'Apple' }, { name: 'Banana' }, { name: 'Fruit loops' }],
  },
  {
    name: 'Vegetables',
    children: [
      {
        name: 'Green',
        children: [{ name: 'Broccoli' }, { name: 'Brussels sprouts' }],
      },
      {
        name: 'Orange',
        children: [{ name: 'Pumpkins' }, { name: 'Carrots' }],
      },
    ],
  },
];

addObjectBefore(data, 'Pumpkins', { name: 'new name' });

// Output the modified data
console.log(data);
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  2. 0

    After calling Array::findIndex you should actually check whether the index is found, it should be >= 0:

    const data = [
  {
    name: 'Fruit',
    children: [{ name: 'Apple' }, { name: 'Banana' }, { name: 'Fruit loops' }],
  },
  {
    name: 'Vegetables',
    children: [
      {
        name: 'Green',
        children: [{ name: 'Broccoli' }, { name: 'Brussels sprouts' }],
      },
     {
        name: 'Orange',
        children: [{ name: 'Pumpkins' }, { name: 'Carrots' }],
      },
    ],
  },
];

insert(data, 'Pumpkins', {name: 'newname'});

console.log(data);


function insert(data, name, what){
  for(const child of data){
    if(child.children){
      const foundIdx = child.children.findIndex(item => item.name === name);
      if(foundIdx >= 0){
        child.children.splice(foundIdx + 1, 0, what);
        return true;
      }
      if(insert(child.children, name, what)){
        return true;
      }
    }
  }
   
}
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