Determine whether there is only one array in the object that contains values

Question

Determine whether there is only one array in the object that contains values

At the moment, I am attempting to examine an array in order to determine if only one of its elements contains data. Consider this sample array:

playersByGender = {
  mens: [],
  womens: [],
  other: []
};

Any combination of these elements may contain data, with just one being filled out. Is there a way to check all three and generate a boolean value indicating if only one is populated?

I initially considered using a foreach loop, but it seems that this method cannot be applied directly to an object.

Any assistance or suggestions would be greatly appreciated. Thank you!

javascript arrays typescript object

Answer 1

Answer №1

Loop through the object's keys using Array#reduce. If an array has a length greater than 0, increment the sum by 1. Finally, compare the final sum to return a Boolean value.

const playersByGender = {
  mens: [],
  womens: [1, 2],
  other: []
};

const onlyOne = (obj) => Object.keys(obj).reduce((sum, k) => obj[k].length > 0 ? sum + 1 : sum, 0) === 1;

console.log(onlyOne({
  mens: [],
  womens: [1, 2],
  other: []
}));

console.log(onlyOne({
  mens: [],
  womens: [1, 2],
  other: [1]
}));

Answer 2

Loop through the object's keys using Array#reduce. If an array has a length greater than 0, increment the sum by 1. Finally, compare the final sum to return a Boolean value.

const playersByGender = {
  mens: [],
  womens: [1, 2],
  other: []
};

const onlyOne = (obj) => Object.keys(obj).reduce((sum, k) => obj[k].length > 0 ? sum + 1 : sum, 0) === 1;

console.log(onlyOne({
  mens: [],
  womens: [1, 2],
  other: []
}));

console.log(onlyOne({
  mens: [],
  womens: [1, 2],
  other: [1]
}));

Answer 3

Answer №2

let groupByAge = {
  young: [],
  old: [4,5],
  other: []
};

console.log(Object.values(groupByAge).filter(a => a.length > 0).length === 1);

Object.values is used to extract all values from the object, then we filter out non-empty arrays and count them using

.filter(a => a.length > 0).length

Answer 4

let groupByAge = {
  young: [],
  old: [4,5],
  other: []
};

console.log(Object.values(groupByAge).filter(a => a.length > 0).length === 1);

Object.values is used to extract all values from the object, then we filter out non-empty arrays and count them using

.filter(a => a.length > 0).length

Answer 5

Answer №3

To achieve the desired outcome, it is recommended to utilize a for in loop instead of foreach. The for in loop allows you to iterate through the properties of your object, check the length of each array within the object, and determine if any of them have values.

Only 1:

var playersByGender = {
    mens: [1],
    womens: [],
    other: []
  },
  oneArrayLength = false;

for(var key in playersByGender) {
  if(playersByGender.hasOwnProperty(key)) {
    if(playersByGender[key].length) {
      if(!oneArrayLength) {
        oneArrayLength = true;
      } else {
        oneArrayLength = false;
        break;
      }
    }
  }
}

console.log(oneArrayLength);

More than 1:

var playersByGender = {
    mens: [1],
    womens: [1],
    other: []
  },
  oneArrayLength = false;

for(var key in playersByGender) {
  if(playersByGender.hasOwnProperty(key)) {
    if(playersByGender[key].length) {
      if(!oneArrayLength) {
        oneArrayLength = true;
      } else {
        oneArrayLength = false;
        break;
      }
    }
  }
}

console.log(oneArrayLength);

Edit:

The code has been adjusted based on the requirement mentioned, ensuring that the result is only true when exactly one of the arrays contains values.

Answer 6

To achieve the desired outcome, it is recommended to utilize a for in loop instead of foreach. The for in loop allows you to iterate through the properties of your object, check the length of each array within the object, and determine if any of them have values.

Only 1:

var playersByGender = {
    mens: [1],
    womens: [],
    other: []
  },
  oneArrayLength = false;

for(var key in playersByGender) {
  if(playersByGender.hasOwnProperty(key)) {
    if(playersByGender[key].length) {
      if(!oneArrayLength) {
        oneArrayLength = true;
      } else {
        oneArrayLength = false;
        break;
      }
    }
  }
}

console.log(oneArrayLength);

More than 1:

var playersByGender = {
    mens: [1],
    womens: [1],
    other: []
  },
  oneArrayLength = false;

for(var key in playersByGender) {
  if(playersByGender.hasOwnProperty(key)) {
    if(playersByGender[key].length) {
      if(!oneArrayLength) {
        oneArrayLength = true;
      } else {
        oneArrayLength = false;
        break;
      }
    }
  }
}

console.log(oneArrayLength);

Edit:

The code has been adjusted based on the requirement mentioned, ensuring that the result is only true when exactly one of the arrays contains values.

Answer 7

Answer №4

If you want to iterate through arrays, determine their lengths, filter out those with none, and then calculate the count, there are multiple approaches available for achieving this goal. Various methods have been suggested by others, showcasing different ways of accomplishing the task. It is advisable to acquaint yourself with the array methods provided in JavaScript. Check them out here!

Here's an alternative method along with an explanation:

let arraysWithMoreThanOne = Object.keys(playerByGender).map(function(key) {
  // We start with an array of keys representing men, women, and other
  // Using the map method allows us to transform the key into something else,
  // like the length of the array
  // Only the array lengths are significant
  return playersByGender[key].length;
}).filter(function(count) {
   // The filter method helps eliminate items we aren't interested in
   // We only want those with more than one item
   return count > 0;
}) // By the end, we convert the object into a different result
.length; // This shows the number of arrays containing more than one item

In certain environments, additional support may be required for some methods.

Answer 8

If you want to iterate through arrays, determine their lengths, filter out those with none, and then calculate the count, there are multiple approaches available for achieving this goal. Various methods have been suggested by others, showcasing different ways of accomplishing the task. It is advisable to acquaint yourself with the array methods provided in JavaScript. Check them out here!

Here's an alternative method along with an explanation:

let arraysWithMoreThanOne = Object.keys(playerByGender).map(function(key) {
  // We start with an array of keys representing men, women, and other
  // Using the map method allows us to transform the key into something else,
  // like the length of the array
  // Only the array lengths are significant
  return playersByGender[key].length;
}).filter(function(count) {
   // The filter method helps eliminate items we aren't interested in
   // We only want those with more than one item
   return count > 0;
}) // By the end, we convert the object into a different result
.length; // This shows the number of arrays containing more than one item

In certain environments, additional support may be required for some methods.

Answer 9

Answer №5

To check if any of the arrays in playersByGender contain data, you can use a for..in loop like this:

function checkIfDataExists(arr) {
  var dataExists = false;
  for (var prop in arr) {
    if (playersByGender[prop].length) dataExists = true;
  }
  return dataExists;
}

var dataFound = checkIfDataExists(playersByGender);

Answer 10

To check if any of the arrays in playersByGender contain data, you can use a for..in loop like this:

function checkIfDataExists(arr) {
  var dataExists = false;
  for (var prop in arr) {
    if (playersByGender[prop].length) dataExists = true;
  }
  return dataExists;
}

var dataFound = checkIfDataExists(playersByGender);

Determine whether there is only one array in the object that contains values

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

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