Steps for storing a JSON string containing several objects into a JavaScript variable

Question

Steps for storing a JSON string containing several objects into a JavaScript variable

I'm working with a JSON that contains multiple objects, and it's possible for this JSON string to have more data/objects than just three. My goal is to create an array of objects regardless of how much information is included.

[ {"endDate":"2017-04-18","nrC":2,"type":"CO","dataD":"2017-04-19","startDate":"2017-04-16"},  
  {"endDate":"2017-04-27","nrC":4,"type":"CP","dataD":"2017-04-23","startDate":"2017-03-26"},  
  {"endDate":"2017-04-27","nrC":7,"type":"CA","dataD":"2017-04-23","startDate":"2017-04-26"}
]

var USER_DAYS = {};

for(var i=0;i<json.length;i++){   
    var USER_DAYS = [  
      {
          id: json[i].nrC,
          date: json[i].dataD,
          title: json[i].type,
          start: new Date(json[i].startDate),
          end: new Date(json[i].endDate),
          allDay: true
      },            
    ];

    console.log(i); // displays 1, 2, 3
}

console.log(USER_DAYS) // shows only the last object from the json.

The JavaScript variable USER_DAYS should be an array containing n objects when printed, but currently only one object is being displayed in my console instead of the desired three.

I am looking to populate the USER_DAYS variable with all objects from the JSON provided.

javascript arrays json

Answer 1

Answer №1

With each iteration of the loop, a new array is created and the previous one is discarded.

To optimize performance, initialize the array outside the loop.

Add a new object to the array during each iteration of the loop.

// Use of ALL CAPS convention is typically reserved for constants. 
// Since you're not dealing with constants here, avoid using ALL CAPS
var userDays = []; // Define and initialize the array outside the loop
for (var i = 0; i < json.length; i++) {
    // It's important to note that you're creating an object named `user_day` inside the loop
    var userDay = {
        id: json[i].nrC,
        date: json[i].dataD,
        title: json[i].type,
        start: new Date(json[i].startDate),
        end: new Date(json[i].endDate),
        allDay: true
    };

    // Add the created object to the array
    userDays.push(userDay);
}
console.log(userDays);

Answer 2

With each iteration of the loop, a new array is created and the previous one is discarded.

To optimize performance, initialize the array outside the loop.

Add a new object to the array during each iteration of the loop.

// Use of ALL CAPS convention is typically reserved for constants. 
// Since you're not dealing with constants here, avoid using ALL CAPS
var userDays = []; // Define and initialize the array outside the loop
for (var i = 0; i < json.length; i++) {
    // It's important to note that you're creating an object named `user_day` inside the loop
    var userDay = {
        id: json[i].nrC,
        date: json[i].dataD,
        title: json[i].type,
        start: new Date(json[i].startDate),
        end: new Date(json[i].endDate),
        allDay: true
    };

    // Add the created object to the array
    userDays.push(userDay);
}
console.log(userDays);

Answer 3

Answer №2

It is important to avoid overwriting your variable in each iteration, like this:

USER_DAYS[i]   = {
                   id: json[i].nrC,
                   date: json[i].dataD,
                   title: json[i].type,
                   start: new Date(json[i].startDate),
                   end: new Date(json[i].endDate),
                   allDay: true
                 }

Make sure to define your Array before the for loop as shown below:

Here's an example:

var json = [{
    "endDate": "2017-04-18",
    "nrC": 2,
    "type": "CO",
    "dataD": "2017-04-19",
    "startDate": "2017-04-16"
  },
  {
    "endDate": "2017-04-27",
    "nrC": 4,
    "type": "CP",
    "dataD": "2017-04-23",
    "startDate": "2017-03-26"
  },
  {
    "endDate": "2017-04-27",
    "nrC": 7,
    "type": "CA",
    "dataD": "2017-04-23",
    "startDate": "2017-04-26"
  }
];

var USER_DAYS = [];

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

  USER_DAYS[i] = {
    id: json[i].nrC,
    date: json[i].dataD,
    title: json[i].type,
    start: new Date(json[i].startDate),
    end: new Date(json[i].endDate),
    allDay: true
  };

  console.log(i); // prints 1,2,3
}

console.log(USER_DAYS) //prints the generated Array

Answer 4

It is important to avoid overwriting your variable in each iteration, like this:

USER_DAYS[i]   = {
                   id: json[i].nrC,
                   date: json[i].dataD,
                   title: json[i].type,
                   start: new Date(json[i].startDate),
                   end: new Date(json[i].endDate),
                   allDay: true
                 }

Make sure to define your Array before the for loop as shown below:

Here's an example:

var json = [{
    "endDate": "2017-04-18",
    "nrC": 2,
    "type": "CO",
    "dataD": "2017-04-19",
    "startDate": "2017-04-16"
  },
  {
    "endDate": "2017-04-27",
    "nrC": 4,
    "type": "CP",
    "dataD": "2017-04-23",
    "startDate": "2017-03-26"
  },
  {
    "endDate": "2017-04-27",
    "nrC": 7,
    "type": "CA",
    "dataD": "2017-04-23",
    "startDate": "2017-04-26"
  }
];

var USER_DAYS = [];

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

  USER_DAYS[i] = {
    id: json[i].nrC,
    date: json[i].dataD,
    title: json[i].type,
    start: new Date(json[i].startDate),
    end: new Date(json[i].endDate),
    allDay: true
  };

  console.log(i); // prints 1,2,3
}

console.log(USER_DAYS) //prints the generated Array

Answer 5

Answer №3

To properly analyze the JSON string, make sure to utilize JSON.parse:

JSON.parse('[ {"endDate":"2019-07-14","numC":8,"category":"A","dateAdded":"2019-07-10","startDate":"2019-07-12"},{"endDate":"2019-08-25","numC":6,"category":"B","dateAdded":"2019-08-20","startDate":"2019-08-15"} ]')

Answer 6

To properly analyze the JSON string, make sure to utilize JSON.parse:

JSON.parse('[ {"endDate":"2019-07-14","numC":8,"category":"A","dateAdded":"2019-07-10","startDate":"2019-07-12"},{"endDate":"2019-08-25","numC":6,"category":"B","dateAdded":"2019-08-20","startDate":"2019-08-15"} ]')

Steps for storing a JSON string containing several objects into a JavaScript variable

Answer №1

Answer №2

Answer №3

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