Extract the array of numbers from the JSON file

Question

Extract the array of numbers from the JSON file

My task is to extract an array of numbers from JSON files. I need to handle files that contain only arrays of numbers or one level deeper (referred to as direct arrays). These files may also include other data types such as strings or booleans.

The challenge lies in identifying the array of numbers, as they may be classified as objects when their type is checked.

I must solve this without using any additional libraries. Is there a standard solution available for this issue?

file1.json

[1,2,3,4]

Output:

1,2,3,4

file2.json

{a:'4',b:true,c:[5,6,7]}

Output:

5,6,7

file3.json

{a:[1,'2',3],b:2,c:['1','2','3']}

Output:

[]

The goal is to fulfill a Promise with the sum of numbers extracted and reject it if there are no arrays of numbers or if the JSON files are invalid.

javascript json

Answer 1

Answer №1

When performing a surface level iteration on the object, it becomes essential to distinguish between an object and an array before examining number arrays within. By looping through an array, one can validate each element as a number using the typeof operator. The provided function accepts an object as input and generates an array consisting of number arrays found in the object.

var array1Example = [1, 2, 3];
var array2Example = [1, '2', 3, 'a'];
var object1Example = {
  a: '4',
  b: true,
  c: [5, 6, 7]
};
var object2Example = {
  a: [1, '2', 3],
  b: 2,
  c: ['1', '2', '3']
}


function isArrayOfNumbers(arr) {
  for (var i = 0; i < arr.length; i++) {
    if (typeof arr[i] !== 'number') {
      return false;
    }
  }

  return true;
}

function getNumberArrays(obj) {
  var numArrays = [];
  if (Array.isArray(obj)) {
    if (isArrayOfNumbers(obj)) {
      numArrays.push(obj);
    }
  } else if ((typeof obj === "object") && (obj !== null)) {
    for (var key in obj) {
      if (Array.isArray(obj[key]) && isArrayOfNumbers(obj[key])) {
        numArrays.push(obj[key]);
      }
    }
  }

  return numArrays;
}

console.log(getNumberArrays(array1Example));
console.log(getNumberArrays(array2Example));
console.log(getNumberArrays(object1Example));
console.log(getNumberArrays(object2Example));

Answer 2

When performing a surface level iteration on the object, it becomes essential to distinguish between an object and an array before examining number arrays within. By looping through an array, one can validate each element as a number using the typeof operator. The provided function accepts an object as input and generates an array consisting of number arrays found in the object.

var array1Example = [1, 2, 3];
var array2Example = [1, '2', 3, 'a'];
var object1Example = {
  a: '4',
  b: true,
  c: [5, 6, 7]
};
var object2Example = {
  a: [1, '2', 3],
  b: 2,
  c: ['1', '2', '3']
}


function isArrayOfNumbers(arr) {
  for (var i = 0; i < arr.length; i++) {
    if (typeof arr[i] !== 'number') {
      return false;
    }
  }

  return true;
}

function getNumberArrays(obj) {
  var numArrays = [];
  if (Array.isArray(obj)) {
    if (isArrayOfNumbers(obj)) {
      numArrays.push(obj);
    }
  } else if ((typeof obj === "object") && (obj !== null)) {
    for (var key in obj) {
      if (Array.isArray(obj[key]) && isArrayOfNumbers(obj[key])) {
        numArrays.push(obj[key]);
      }
    }
  }

  return numArrays;
}

console.log(getNumberArrays(array1Example));
console.log(getNumberArrays(array2Example));
console.log(getNumberArrays(object1Example));
console.log(getNumberArrays(object2Example));

Answer 3

Answer №2

This method employs recursive techniques to scan for nested arrays.

var arr = ['[1,2,3,4]','{"a":"4","b":true,"c":[5,6,7]}','{"a":[1,"2",3],"b":2,"c":["1","2","3"]}','{xds}'];
var index, subIndex, len = arr.length;

function checkForArray(value, depth) {
        var element, filteredArr;
        
        if (depth > 1) {
                return false;
        }
        
        if (Array.isArray(value)) {
                filteredArr = value.filter( function(element) {
                        return (isNaN(element) || typeof element === "string");
                });
                
                if (filteredArr.length === 0) {
                        return true;
                } else {
                        return false;
                }
        } else {
        
                if (typeof value === "object") {
                        for (element in value) {
                                if (checkForArray(value[element], depth+1) === false) {
                                        return false;
                                }
                        }
                        return true;
                }
        }
        
        return null;
}

for (index = 0; index < len; index++) {
        console.log(arr[index]);
        try {
                subIndex = JSON.parse(arr[index]);
                console.log(checkForArray(subIndex, 0));
        } catch (error) {
                console.log('Error caught: '+ error);
        }
}

Answer 4

This method employs recursive techniques to scan for nested arrays.

var arr = ['[1,2,3,4]','{"a":"4","b":true,"c":[5,6,7]}','{"a":[1,"2",3],"b":2,"c":["1","2","3"]}','{xds}'];
var index, subIndex, len = arr.length;

function checkForArray(value, depth) {
        var element, filteredArr;
        
        if (depth > 1) {
                return false;
        }
        
        if (Array.isArray(value)) {
                filteredArr = value.filter( function(element) {
                        return (isNaN(element) || typeof element === "string");
                });
                
                if (filteredArr.length === 0) {
                        return true;
                } else {
                        return false;
                }
        } else {
        
                if (typeof value === "object") {
                        for (element in value) {
                                if (checkForArray(value[element], depth+1) === false) {
                                        return false;
                                }
                        }
                        return true;
                }
        }
        
        return null;
}

for (index = 0; index < len; index++) {
        console.log(arr[index]);
        try {
                subIndex = JSON.parse(arr[index]);
                console.log(checkForArray(subIndex, 0));
        } catch (error) {
                console.log('Error caught: '+ error);
        }
}

Extract the array of numbers from the JSON file

Answer №1

Answer №2

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