Javascript function to modify the array of objects reuturns the same array-CodePudding

I have a data inside of my array, which looks like this.

const arr = [
  {
  devSth: {
    h1: [1],
    h2: [1],
  }
 },
];

I have a function, which should modify this array. It looks like this:

const modifyArr = (data) => {
 data.forEach(el => {
  let keys = el.devSth && Object.keys(el.devSth);
  keys.forEach(key => {
    el.devSth[key].map(el => {
    return {
    name: el,
    val: 'lalala'
    }
    })
  })
})
return data;
}

Then I am using my function:

const newArr = modifyArr(arr);
console.log(newArr);

Expected output:

[{
  devSth: {
    h1: [{name: 1, val: 'lalala'}],
    h2: [{name: 1, val: 'lalala'}]
  }
}]

Actual output:

[{
  devSth: {
    h1: [1],
    h2: [1]
  }
}]

Would appreciate any help.

CodePudding user response：

you are mapping the values, but not setting them (line 5) :

const modifyArr = (data) => {
 data.forEach(el => {
  let keys = el.devSth && Object.keys(el.devSth);
  keys.forEach(key => {
    el.devSth[key] = el.devSth[key].map(el => {
    return {
    name: el,
    val: 'lalala'
    }
    })
  })
})
return data;
}

this is untested.

CodePudding user response：

You dont assign the result of the .map operation back to the original keys h1 and h2. Just change

            el.devSth[key].map(el => {
                console.log("a")
                return {
                    name: el,
                    val: 'lalala'
                }
            })

            el.devSth[key] = el.devSth[key].map(el => {
                console.log("a")
                return {
                    name: el,
                    val: 'lalala'
                }

const arr = [{
  devSth: {
    h1: [1],
    h2: [1],
  }
}, ];

const modifyArr = (data) => {
  data.forEach(el => {
    let keys = el.devSth && Object.keys(el.devSth);
    keys.forEach(key => {
      el.devSth[key] = el.devSth[key].map(el => {
        console.log("a")
        return {
          name: el,
          val: 'lalala'
        }
      })
    })
  })
  return data;
}

const newArr = modifyArr(arr);
console.log(newArr);