Find number of times a property has a truthy value in a nested object

Question

I have a nested object and I would like to calculate the number of times the property 'error'. I am able to go n levels deep and find the count. Is there a better solution than mine?

const data = {
 "item1": {
 "value": 88,
 "error": false
 },
 "item2": {
 "value": 651,
 "error": false
 },
 "item3": false,
 "item4": [],
 "item5": "",
 "item6": "",
 "item7": false,
 "item8": {
 "error": true
 },
 "item9": {
 "value": [],
 "error": true
 },
 "item10": {
 "value": [],
 "error": true
 },
 "item11": {
 "value": [],
 "error": true
 },
 "item12": false,
 "item13": {
 "subItem1": {
 "name": "Country",
 "groups": {},
 "instances": [],
 "error": true
 },
 "subItem2": {
 "name": "Group",
 "groups": {},
 "instances": [],
 "error": true
 },
 "subItem3": {
 "name": "Product",
 "groups": {},
 "instances": [],
 "error": true
 }
 }
}
function traverseAndFlatten(currentNode, target, flattenedKey) {
 for (var key in currentNode) {
 if (currentNode.hasOwnProperty(key)) {
 var newKey;
 if (flattenedKey === undefined) {
 newKey = key;
 } else {
 newKey = flattenedKey + '.' + key;
 }
 var value = currentNode[key];
 if (typeof value === "object") {
 traverseAndFlatten(value, target, newKey);
 } else {
 target[newKey] = value;
 }
 }
 }
}
function flatten(obj) {
 var flattenedObject = {};
 traverseAndFlatten(obj, flattenedObject);
 return flattenedObject;
}
var flattened = flatten(data);
const keys = _.keys(flattened);
const errorCount = _.map(keys, key => {
 let count = 0;
 if (key.includes('.error') && flattened[key]) {
 count++
 }
 return count
})
console.log(_.sumBy(errorCount))

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• Sᴀᴍ Onᴇᴌᴀ: Given that the code uses lodash, when you state "I am open to use lodash as well." did you actually mean that you are open to not using lodash?
• arunmmanoharan: I am open to using lodash. I will fix the OP
• Sᴀᴍ Onᴇᴌᴀ: Are you also open to vanilla JS i.e. without lodash?
• Sᴀᴍ Onᴇᴌᴀ: please clarify what qualifies as "better" - fewer lines of code? faster? uses less memory?
• tsh: Maybe not the best idea, but could be easiest to implement: count = 0; JSON.stringify(data, function (x, y) { if (x === 'error' && y) count++; return y; }); alert(count);

Answer 1

The comment recommending JSON.stringify is a bit faster, but it is in the range of <1 microsecond

const data = {
 "item1": {
 "value": 88,
 "error": false
 },
 "item2": {
 "value": 651,
 "error": false
 },
 "item3": false,
 "item4": [],
 "item5": "",
 "item6": "",
 "item7": false,
 "item8": {
 "error": true
 },
 "item9": {
 "value": [],
 "error": true
 },
 "item10": {
 "value": [],
 "error": true
 },
 "item11": {
 "value": [],
 "error": true
 },
 "item12": false,
 "item13": {
 "subItem1": {
 "name": "Country",
 "groups": {},
 "instances": [],
 "error": true
 },
 "subItem2": {
 "name": "Group",
 "groups": {},
 "instances": [],
 "error": true
 },
 "subItem3": {
 "name": "Product",
 "groups": {},
 "instances": [],
 "error": true
 }
 }
}
function traverseAndFlatten(currentNode, target, flattenedKey) {
 for (var key in currentNode) {
 if (currentNode.hasOwnProperty(key)) {
 var newKey;
 if (flattenedKey === undefined) {
 newKey = key;
 } else {
 newKey = flattenedKey + '.' + key;
 }
 var value = currentNode[key];
 if (typeof value === "object") {
 traverseAndFlatten(value, target, newKey);
 } else {
 target[newKey] = value;
 }
 }
 }
}
function flatten(obj) {
 var flattenedObject = {};
 traverseAndFlatten(obj, flattenedObject);
 return flattenedObject;
}
let startTime = performance.now()
var flattened = flatten(data);
const keys = _.keys(flattened);
const errorCount = _.map(keys, key => {
 let count = 0;
 if (key.includes('.error') && flattened[key]) {
 count++
 }
 return count
})
let count =_.sumBy(errorCount)
let endTime = performance.now()
console.log(count)
console.log(`Call to count error took ${endTime - startTime} milliseconds`)
startTime = performance.now()
count = 0;
JSON.stringify(data, function (x, y) { if (x === 'error' && y) count++; return y; });
endTime=performance.now()
console.log(count)
console.log(`Call to count error 2 took ${endTime - startTime} milliseconds`)

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