Adding values to existing key in object Javascript - Stack Overflow

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How do I add more names to an age group in object with simple javascript? Not using any built in function like reduce(), append(), assign() etc. Please let me know my mistakes and what I am missing. Any help is appreciated :)

My output is { '10': [ 'Victoria' ], '12': [ 'Samantha' ] } My second 'if' statement never executed

Expected Output:

{
"12": ["Kathy", "Krystal", "Samantha"],
"10": ["Victoria"]
}

const ageGroup = function(girls) {

  let people = {};

  for (let i = 0; i < girls.length; i++) {
    if (girls[i].age !== people.age) {
      people[girls[i].age] = [girls[i].name];

    }
    if (girls[i].age === people.age) {
      people.push([girls[i].name]);
    }

  }
  return people;

};

console.log(ageGroup([{
    name: "Kathy",
    age: 12
  },
  {
    name: "Victoria",
    age: 10
  },
  {
    name: "Krystal",
    age: 12
  },
  {
    name: "Samantha",
    age: 12
  }
]));

How do I add more names to an age group in object with simple javascript? Not using any built in function like reduce(), append(), assign() etc. Please let me know my mistakes and what I am missing. Any help is appreciated :)

My output is { '10': [ 'Victoria' ], '12': [ 'Samantha' ] } My second 'if' statement never executed

Expected Output:

{
"12": ["Kathy", "Krystal", "Samantha"],
"10": ["Victoria"]
}

const ageGroup = function(girls) {

  let people = {};

  for (let i = 0; i < girls.length; i++) {
    if (girls[i].age !== people.age) {
      people[girls[i].age] = [girls[i].name];

    }
    if (girls[i].age === people.age) {
      people.push([girls[i].name]);
    }

  }
  return people;

};

console.log(ageGroup([{
    name: "Kathy",
    age: 12
  },
  {
    name: "Victoria",
    age: 10
  },
  {
    name: "Krystal",
    age: 12
  },
  {
    name: "Samantha",
    age: 12
  }
]));

• javascript

Share Improve this question Follow edited Apr 2, 2021 at 4:48 Russell 4255 bronze badges asked Apr 2, 2021 at 1:43 ElizawtwElizawtw 311 silver badge22 bronze badges

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4 Answers 4

Sorted by: Reset to default 2

I edited your code so it works better now!

const ageGroup = function(girls) {
  
  let people = {}; // Create "people" object
  
  for (let girl of girls) { // For each item in "girls",
    
    const age = girl.age; // Get the age of the girl
    const name = girl.name; // Get the name of the girl
    
    if (age in people) { // If the current age is already a key in "people",
      people[age].push(name); // Push the girl's name to the array.
    }
    else { // Otherwise (if the current age is not yet a key in "people"),
      people[age] = [name]; // Set it to an array with the one name in it.
    }
  }
  return people;

};

console.log(ageGroup([
  {name: "Kathy", age: 12},
  {name: "Victoria", age: 10},
  {name: "Krystal", age: 12},
  {name: "Samantha", age: 12}
]));

Your first if condition is always meeting, thats why it never moves on to the next one. girls.age will never be equal to people.age since you dont have any value stored in people.age when function runs. So it is not your code, you should find another way to make the control. For adding objects to arrays, simply use .map and on every item in the array that you want to add objects, specify the object inside the callback function of the .map method. Of course you can do it in a for loop as well but since we have the built-in methods it is way more convenient to employ them.

Your initial check should be to see if the object key exists. If not, create a new object key with a one-element array. If the key does exist, then just append the name to the existing array.

const ageGroup = function(girls) {
  let people = {};
  for(let i = 0; i < girls.length; i++){
    if(!people[girls[i].age]){
      people[girls[i].age] = [girls[i].name];
    } else {
      people[girls[i].age].push(girls[i].name);
    }
  }
  return people;

};

console.log(ageGroup([
  {name: "Kathy", age: 12},
  {name: "Victoria", age: 10},
  {name: "Krystal", age: 12},
  {name: "Samantha", age: 12}
]));

This is my solution:

const ageGroup = function(girls){
    let result={};
  for (let i=0;i<girls.length;i++){
    if (result[girls[i].age]){
        result[girls[i].age].push(girls[i].name);
    } else {
        result[girls[i].age]=[girls[i].name];
    }  
  }
  return result;
}
console.log(ageGroup([
  {name: "Kathy", age: 12},
  {name: "Victoria", age: 10},
  {name: "Krystal", age: 12},
  {name: "Samantha", age: 12}
]));

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