Question 110380 in Json Question posted in
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Failed to console unique names from JSON array

I have a JSON array having hundreds of objects where each JSON object having name and hobbies property.

Below is the JSON structure:

 const data = [
 {
  name:'Paul',
  hobbies: ['Football','Reading']
 },
 {
  name:'Riya',
  hobbies: ['Singing','Dancing']
 },
 {
  name:'Jack',
  hobbies: ['Gaming']
 }
]

So here if I will iterate through this data it will give me same name multiple times wherever multiple hobbies are present.So if I am console it result would be

Paul,Football
Paul,Reading
Riya,Singing
Riya,Dancing
Jack,Gaming

I don’t want above output I want wherever there is same name is coming in a same object don’t console it like below:

Paul,Football
"",Reading
Riya,Singing
"",Dancing
Jack,Gaming

Below is my code:

  const data = [
  {
   name:'Paul',
   hobbies: ['Football','Reading']
  },
  {
   name:'Riya',
   hobbies: ['Singing','Dancing']
  },
  {
   name:'Jack',
   hobbies: ['Gaming']
  }
 ]

const example = (data) => {

for(var i=0;i<data.length;i++){

    for(var j=0;j<data[i].hobbies.length;j++){

        console.log(data[i].name,data[i].hobbies[j]);

         if(i=0){
           console.log(data[i].name,data[i].reports[j]);
        }
        else{
            const prev = i-1;
            if(data[prev].name == data[i].name) { //Getting TypeError here cannot read property 'name' of undefined 
               console.log("",data[i].reports[j]);
            }
            else{
               console.log(data[i].name,data[i].reports[j]); 
            }
        }
      }
    }
 }

example(data);

In above code I am trying to compare the previous value of name in data array with the current value of name. If it’s same then making name field " " else putting name value and for first element for position 0 I am putting value as it is.

Why am I getting this TypeError?

Tags:

2

Answers


  1. 0 
    const data = [
 {
  name:'Paul',
  hobbies: ['Football','Reading']
 },
 {
  name:'Riya',
  hobbies: ['Singing','Dancing']
 },
 {
  name:'Jack',
  hobbies: ['Gaming']
 }
]

data.forEach(d => {
  d.hobbies.forEach((hobby, index) => {
    const name = index == 0 ? d.name : '""'
    console.log(name + ',' + hobby)
  })
})

    Just print the name if index of hobby is 0

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  2. 0

    There are several issues, first is typo, you assigned instead of comparing

    if (i=0) {
// ^^^^^
  console.log(data[i].name,data[i].reports[j]);
}

    The rest is logic, all you have to do is to check the index of j

    const example = data => {
  for (var i = 0; i < data.length; i++) {
    for (var j = 0; j < data[i].hobbies.length; j++) {
      if (j == 0) {
        console.log(data[i].name, data[i].hobbies[j])
      } else {
        console.log("", data[i].hobbies[j])
      }
    }
  }
}

    Full solution

    const data = [
  {
    name: "Paul",
    hobbies: ["Football", "Reading"],
  },
  {
    name: "Riya",
    hobbies: ["Singing", "Dancing"],
  },
  {
    name: "Jack",
    hobbies: ["Gaming"],
  },
]

const example = data => {
  for (var i = 0; i < data.length; i++) {
    for (var j = 0; j < data[i].hobbies.length; j++) {
      if (j == 0) {
        console.log(data[i].name, data[i].hobbies[j])
      } else {
        console.log("", data[i].hobbies[j])
      }
    }
  }
}

example(data)
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