I want to get the length of values from an object. If the value has no length i should get 0 length, if value exists i should get value.
const object1 = {
a: '',
b: '5'
};
function app() {
for (const [key, value] of Object.entries(object1)) {
console.log(key, value)
return {
[key]: !object1[key].length ? '0 length' : value
}
}
}
console.log(app())
Question:
Why i get just first value from object?
{
"a": "0 length"
}
expect:
{
"a": "0 length",
"b": 1
}
Why now i get in console.log(key, value) just the first value-key, but if i delete the return statement i get both value-key?
const object1 = {
a: '',
b: '5'
};
function app() {
for (const [key, value] of Object.entries(object1)) {
console.log(key, value)
// return {
// [key] : !object1[key].length ? '0 length' : value
// }
}
}
console.log(app())
Because you are returning from very first value inside for you are getting only one value in result.
Instead of that take one variable for ex let result = {}; Assign length values to it inside for as result[key] = value.toString().length || '0 length'; and then return result;.
Try it below.
const object1 = {
a: '',
b: '5'
};
function app() {
let result = {};
for (const [key, value] of Object.entries(object1)) {
// console.log(key, value)
result[key] = value.toString().length || '0 length';
}
return result;
}
console.log(app());
If your expected output is array then use like below. For array result you can also use map with like shown in app2.
const object1 = {
a: '',
b: '5'
};
function app() {
let result = [];
for (const [key, value] of Object.entries(object1)) {
result.push({[key]: value.toString().length || '0 length'});
}
return result;
}
function app2() {
return Object.entries(object1).map(([key, value]) => ({[key]: value.toString().length || '0 length'}));
}
console.log(app());
console.log(app2());
return exits the loop after first iteration
Perhaps you should do something like this
const object1 = {
a: '',
b: '5'
};
const newObj = {};
function app() {
for (const [key, value] of Object.entries(object1)) {
console.log(key, value)
newObj[key] = !object1[key].length ? '0 length' : value
}
return newObj;
}
console.log(app())
const object1 = {
a: '',
b: '5'
};
function app() {
const result = [];
for(let key in object1) {
if(object1[key] && object1[key].length) {
result.push({[key] :`${object1[key].length} length`});
} else {
result.push({[key] :`0 length`});
}
}
return result;
}
console.log(app())
Related
If this is my object
{
"a":{
"a1":5,
"b":{
"b1":10,
"b2":15,
"c":{
"c1":15
}
}
}
}
the output I want is:
{a:45 b:40, c: 15}
c => 15
b => 10 + 15 + c
a => 5 + b + c
how do I achieve this? been banging my head against a brick wall all day
so far I've tried:
let constructedTotals = {};
const calculateVals = (vals) => {
return vals
.map((val) => {
if (typeof val === "object" && Object.keys(val).length > 0) {
return Object.values(val);
}
return val;
})
.flatMap((x) => x)
.filter((x) => typeof x === "number")
.reduce((a, b) => a + b, 0);
};
const constructing = (construct) => {
return Object.entries(construct).map((entry) => {
if (typeof entry[1] === "object") {
constructing(entry[1]);
constructedTotals = {
...constructedTotals,
[entry[0]]: calculateVals(Object.values(entry[1])),
};
} else {
console.log('here')
}
});
};
const data = {
a: {
a1: 5,
b: {
b1: 10,
b2: 15,
c: {
c1: 15,
},
},
},
};
const outputObj = {};
function addValue(data) {
for (const [key, value] of Object.entries(data)) {
const outKey = key.at(0);
outputObj[outKey] ??= 0;
if (typeof value === "object") addValue(value);
else for (const svKey in outputObj) outputObj[svKey] += value;
}
}
addValue(data);
console.log(outputObj);
You could handover the parent key and add the total of nested keys.
const
sum = (object, parent = '') => Object
.entries(object)
.reduce((r, [k, v]) => {
if (v && typeof v === 'object') {
Object.assign(r, sum(v, k));
if (parent) r[parent] += r[k];
} else {
r[parent] = (r[parent] || 0) + v;
}
return r;
}, {}),
data = { a: { a1: 5, b: { b1: 10, b2: 15, c: { c1: 15 } } } },
result = sum(data);
console.log(result);
You could create a reducer function that:
Builds an object by key
Accumulates the total of the numbered keys for each node, and adds the previous total
const main = () => {
const result = reduce(tree, (acc, node) => {
let currKey, prevKey, currVal = 0;
for (const prop in node) {
const [, key] = prop.match(/^(\w)\d$/) ?? [];
currKey ??= key;
if (key) currVal += +node[prop];
prevKey ??= prop.match(/^(\w)$/)?.[1];
}
if (currKey) {
acc[currKey] = (acc[prevKey] ?? 0) + currVal;
}
});
console.log(result); // { "c": 15, "b": 40, "a": 45 }
};
const reduce = (node, visitor) => {
const result = {};
traverse(node, visitor, result);
return result;
};
const traverse = (node, visitor, result) => {
if (typeof node === 'object') {
for (const prop in node) {
traverse(node[prop], visitor, result);
}
}
visitor(result, node);
};
const tree = {
a: {
a1: 5,
b: {
b1: 10,
b2: 15,
c: {
c1: 15
}
}
}
};
main();
.as-console-wrapper { top: 0; max-height: 100% !important; }
you can try this:
let obj = {
"a":{
"a1":5,
"b":{
"b1":10,
"b2":15,
"c":{
"c1":15
}
}
}
}
let recusive = (obj,output)=>{
if(typeof(obj) == "object"){
let keys = Object.keys(obj)
let sum = 0;
keys.forEach(key => {
if(typeof(obj[key]) == "object"){
output[key] = recusive(obj[key],output)
sum += output[key]
}
else
sum+= obj[key]
});
return sum
}
else
return obj;
}
let warp = (obj) => {
let output = {};
recusive(obj, output);
return output;
}
console.log(warp(obj))
The output will hold the result, it worked for the example you gave, might throw if you give it an object that is build differently
I would like to detect if some values are not defined in an object with several properties
for example :
let test = {
helo: undefined,
hey: "not undefined"
}
i tried this :
const object1 = {
a: 'somestring',
b: 42
};
for (const [key, value] of Object.entries(object1)) {
console.log(`${key}: ${value}`);
}
but if possible, I don't want to use a for loop, I would like a boolean result in return
You could be looking for something like this.
const test = {
helo: undefined,
hey: "not undefined"
};
const some_undefined = Object.values(test).some(v => v === undefined);
console.log(some_undefined);
You can use a function for that :
const hasOneKeyUndefined = (object)=>
{
for (const [key, value] of Object.entries(object)) {
if (value === undefined) return true;
}
return false;
}
You could also use Object.keys
const test = {
helo: undefined,
hey: "not undefined"
};
Object.keys(test).map((key, idx) => test[key] === undefined)
I have an array of object from which I am trying to get values using map operator but I am getting the whole json objects all I want is just array of values.
Below is my code:
const obj = [
{
a: {
b: 'Paul',
}
},
{
c: 'Byeeee',
}
];
obj.map((val) => console.log(val));
what I am getting is
{ a: { b: 'Paul' } }
{ c: 'Byeeee' }
What I want is:
['Paul','Byeeee']
Someone let me know how can I get the desired output.
You can do this recursively. You can first start off by grabbing the values of your object, and then loop through those using .flatMap(). If you encounter a value that is an object, you can recursively grab the values of that object by recalling your function. Otherwise, you can return the value. The advantage of using .flatMap() here is that when the recursive call returns an array, we don't end up with inner arrays, but rather the array gets flattened into one resulting array:
const obj = [{ a: { b: 'Paul', } }, { c: 'Byeeee', } ];
const getValues = (obj) => {
return Object.values(obj).flatMap(val => Object(val) === val ? getValues(val) : val);
}
console.log(getValues(obj));
you can use the following solution.
const data = [{ a: { b: 'Paul' } }, { c: 'Byeeee' }];
const flatObjectValues = (obj, result) => {
// recursive function to get object values
const objValues = Object.values(obj);
if (objValues?.length > 0) {
objValues.map((v) => {
if (typeof v === 'object' && !Array.isArray(v)) {
flatObjectValues(v, result);
} else {
result.push(v);
}
return v;
});
}
};
const updatedData = [];
data.map((x) => flatObjectValues(x, updatedData));
console.log('updatedData: ', updatedData);
You can use recursion with array.reduce, like fellowing.
function getAllValues(objuct) {
return objuct.reduce((acc, curr) => {
if (typeof curr === 'object') {
return [...acc, ...getAllValues(Object.values(curr))];
}
return [...acc, curr];
}, []);
}
A recursive solution could be:
const arr = [{a: {b: "Paul",},},{c: "Byeeee",},];
const flatArrOfObjects = (arr) => {
const values = [];
for (const i in arr) flatObj(arr[i], values);
return values;
};
const flatObj = (obj, result) => {
for (const [key, value] of Object.entries(obj)) {
if (typeof value === "object") flatObj(value, result);
else result.push(value);
}
};
console.log(flatArrOfObjects(arr));
As a part of a challenge I need to implement the .findKey() method myself. Below is the solution proposition, however, I get an error "predicate is not a function".
const _ = {
findKey(object, predicate) {
for (let key in object) {
let value = object[key];
let predicateReturnValue = predicate(value);
if (predicateReturnValue) {
return key;
};
};
undefined
return undefined;
}
};
Can anyone help?
function findKey(object, predicate) {
for (let key in object) {
let value = object[key];
let predicateReturnValue = predicate(value);
if (predicateReturnValue) { // just take the value
return key; // return key
}
}
}
const isEqual = a => b => a === b
const object = { a: 'Apple', b: 'Beer', c: 'Cake' }
alert(findKey(object, isEqual('Apple')));
alert(findKey(object, isEqual('Cakes')));
This question already has answers here:
Remove from JS object where key value is an empty array
(2 answers)
Closed 2 years ago.
I have got object of array. I am trying to check empty.
const data = {
test:[],
test2:[],
test1:["can"]
}
Here is my trying code:
const dataObj = Object.values(data)
console.log(dataObj)
my output would be :
const data = {
test1:["can"]
}
You can use Object.entries and Array#reduce methods.
const data = {
test: [],
test2: [],
test1: ["can"]
}
const res = Object.entries(data).reduce((obj, [k, v]) => {
if (v && v.length) obj[k] = v;
return obj;
}, {})
console.log(res)
Or with for...of loop.
const data = {
test: [],
test2: [],
test1: ["can"]
}
const res = {};
for (let [k, v] of Object.entries(data)) {
if (v && v.length) res[k] = v;
}
console.log(res)
const data = {
test: [],
test2: [],
test1: ["can"],
test3: ["hi"]
}
for (let [key, value] of Object.entries(data)) {
if (value.length) {
console.log(`${key}: not emty`)
} else {
console.log(`${key}: emty`)
}
}