Searching deeply nested object array for a single key - javascript

I am trying to search through a deeply nested array and find if a key exists anywhere inside. I have written up a piece of code which does the traversal, but because it is not recursive (only self calling) it cannot return whether or not it has found anything. It just returns undefined since it reaches the end of the function on one of passes.
I was wondering if there was a way I could do this which would allow me to return true on the first occurrence of a specific key.
Here is a JS bin of what I have been working with so far:
https://jsbin.com/qaxuwajuso/edit?js,console
And here is a direct paste of the code from the above example:
function traverse(item, key) {
if (typeof item === 'object' && !Array.isArray(item) && item !== null) {
// Object
for (let itemKey in item) {
if (itemKey === key) {
// Is it possible to return true and break out of the function here?
console.log('found the key: ' + itemKey + ' With value: ' + item[itemKey]);
}
traverse(item[itemKey], key);
}
} else if (Array.isArray(item)) {
// Array
for (let i = 0; i < item.length; ++i) {
traverse(item[i], key);
}
}
}
Any help would be greatly appreciated. Thank you for your time!

Sure you just need to return a flag of some kind to trigger the loops to stop
/*
* I am trying to search the following json array for any occurance of the key "statePath".
* In a perfect world I would be able to find the first occurance, and return true from the
* function.
*
* The following data is not real, I was just trying to write as much nested stuff as possible
* to test that it traverses as far as needed.
*/
const data = [
{
id: '2144d998-4c33-4b03-93d2-f6c675b24508',
element: 'div',
props: {
className: 'testing',
name: [
{
first: 'John',
last: {
statePath: 'lastName',
anArray: [
{
anObject: {
anotherArray: [
{
doesItWork: {
statePath: 'hello',
},
},
],
},
},
],
},
},
{
first: 'Jane',
last: {
statePath: 'lastName',
},
},
],
},
children: 'hi',
},
];
function traverse(item, key) {
if (typeof item === 'object' && !Array.isArray(item) && item !== null) {
// Object
for (let itemKey in item) {
if (itemKey === key) {
console.log('found the key: ' + itemKey + ' With value: ' + item[itemKey]);
// not sure what you want the end "return" of the func to be, I'm returning the value. You could return true here instead, you could return a reference to the parent object, lots of possibilities
return item[itemKey];
}
var found = traverse(item[itemKey], key);
if (found !== undefined) return found;
// otherwise keep looking
}
} else if (Array.isArray(item)) {
// Array
for (let i = 0; i < item.length; ++i) {
var found = traverse(item[i], key);
if (found !== undefined) return found;
}
}
}
var value = traverse(data, 'statePath');
console.log("value is " + value);

You could use for...in and store result in one var and then check that var before you call function again and break loop if value is found.
const data = [{"id":"2144d998-4c33-4b03-93d2-f6c675b24508","statePath":"div","props":{"className":"testing","name":[{"first":"John","last":{"statePath":"lastName","anArray":[{"anObject":{"anotherArray":[{"doesItWork":{"statePath":"hello"}}]}}]}},{"first":"Jane","last":{"statePath":"lastName"}}]},"children":"hi"}]
function traverse(item, key) {
let result = false;
for (var i in item) {
if (i == key) {
result = true;
break;
}
if (typeof item[i] == 'object' && !result) {
result = traverse(item[i], key)
}
}
return result
}
console.log(traverse(data, 'statePath'))

My variant:
const data = [{id: '2144d998-4c33-4b03-93d2-f6c675b24508', element: 'div', props: {className: 'testing', name: [{first: 'John', last: {statePath3: 'lastName', anArray: [{anObject: {anotherArray: [{doesItWork: {statePath1: 'hello',},},],},},],},}, {first: 'Jane', last: {statePath: 'lastName',},},],}, children: 'hi',},];
function traverse(data, find) {
for (let k in data) {
let deepHaveKey = typeof data[k] === 'object' && traverse(data[k], find)
if (find === k || deepHaveKey)
return true
}
return false
}
console.log(traverse(data, 'statePath')); // true
console.log(traverse(data, 'state')); // false

Related

Add params to function to only execute if value matches name in array

I have an object:
const oData = {
name: 'Hound',
weapon: 'sword',
likes: 'Chicken, Arya, Revenge',
dislikes: 'Fire, Mountain, Lannisters'
};
which I pass to this function:
fConvertValuesToArrays(obj) {
for (const i in obj) {
obj[i] = Array.isArray(obj[i]) ? obj[i] : [obj[i]];
}
return obj;
},
This works as expected in converting all the values into arrays but I now need this to only execute if the value matches with any of the values in this array:
const aNamesToMatch = [ 'likes', 'dislikes' ];
Is it possible to work this into the function or do I need a separate function for this and call that function inside fConvertValuesToArrays?
If so how would that work?
I tried to add an if statement before the ternary but I did not work as expected:
fConvertValuesToArrays(obj) {
for (const i in obj) {
if ( obj.likes || obj.dislikes ) {
obj[i] = Array.isArray(obj[i]) ? obj[i] : [obj[i]];
}
}
return obj;
},
You can use includes() on the array aNamesToMatch. And check if current key is inside that array.
const oData = {
name: 'Hound',
weapon: 'sword',
likes: 'Chicken, Arya, Revenge',
dislikes: 'Fire, Mountain, Lannisters'
};
const aNamesToMatch = [ 'likes', 'dislikes' ];
function fConvertValuesToArrays(obj,keys) {
for (const i in obj) {
if (keys.includes(i)) {
obj[i] = Array.isArray(obj[i]) ? obj[i] : [obj[i]];
}
}
return obj;
}
console.log(fConvertValuesToArrays({...oData},aNamesToMatch))
Instead of looping through the entire object, you can just loop through aNamesToMatch. Update each of those properties in the object to an array:
const aNamesToMatch=['likes','dislikes'],
oData={name:'Hound',weapon:'sword',likes:'Chicken, Arya, Revenge',dislikes:'Fire, Mountain, Lannisters'};
function fConvertValuesToArrays(obj, keys) {
for (const key of keys) {
if (!Array.isArray(obj[key]))
obj[key] = [obj[key]]
}
return obj;
}
console.log(fConvertValuesToArrays(oData, aNamesToMatch))
If there is a possibility of having a key in the array which doesn't exist in the object, you can check if the key exists in the object first:
if (key in obj && !Array.isArray(obj[key])) {
}
Make this change
if(i == 'likes' || i == 'dislikes')
{
obj[i] = Array.isArray(obj[i]) ? obj[i] : [obj[i]];
}
This will check if the key is likes/dislikes and creates an array only if that is the case.

How to deeply remove keys in object?

I have this json object returned from an API that has a few quirks, and I'd like to normalize it so I can process the input the same for every response. These means getting rid of superfluous keys:
Response:
{
_links: {...},
_embedded: {
foo: [
{
id: 2,
_embedded: {
bar: []
}
}
]
}
}
So I'd like to remove all the _embedded keys and flatten it, like so:
{
_links: {...},
foo: [
{
id: 2,
bar: []
}
]
}
This is what I have at the moment, but it only works for the top level and I don't think it'll play well with arrays.
_.reduce(temp1, function(accumulator, value, key) {
if (key === '_embedded') {
return _.merge(accumulator, value);
}
return accumulator[key] = value;
}, {})
Loop in recursion on all of your keys, once you see a key which start with _
simply remove it.
Code:
var
// The keys we want to remove from the Object
KEYS_TO_REMOVE = ['_embedded'],
// The data which we will use
data = {
_links: {'a': 1},
_embedded: {
foo: [
{
id: 2,
_embedded: {
bar: []
}
},
{
id: 3,
_embedded: {
bar: [
{
id: 4,
_embedded: {
bar: []
}
}
]
}
}
]
}
};
/**
* Flatten the given object and remove the desired keys if needed
* #param obj
*/
function flattenObject(obj, flattenObj) {
var key;
// Check to see if we have flatten obj or not
flattenObj = flattenObj || {};
// Loop over all the object keys and process them
for (key in obj) {
// Check that we are running on the object key
if (obj.hasOwnProperty(key)) {
// Check to see if the current key is in the "black" list or not
if (KEYS_TO_REMOVE.indexOf(key) === -1) {
// Process the inner object without this key
flattenObj[key] = flattenObject(obj[key], flattenObj[key]);
} else {
flattenObject(obj[key], flattenObj);
}
}
}
return flattenObj;
}
console.log(flattenObject(data));
So, basically you already have almost all of the code you need. All we have to do is wrap it in a function so we can use recursion. You'll see we only add a check to see if it is an object, if it is, we already have a function that knows how to flatten that object, so we'll just call it again with the key that we need to flatten.
function flatten(temp1) { // Wrap in a function so we can use recursion
return _.reduce(temp1, function(accumulator, value, key) {
if (key === '_embedded') {
return _.merge(accumulator, value);
} else if (value !== null && typeof value === 'object') // Check if it's another object
return _.merge(accumulator, flatten(value)) // Call our function again
return accumulator[key] = value;
}, {})
}
I'll be able to test it in a bit, but this should be what you need.
Got it!
function unEmbed(data) {
return _.reduce(data, function(accumulator, value, key) {
const returnableValue = _.isObject(value) ? unEmbed(value) : value;
if (key === 'embedded') {
return _.merge(accumulator, returnableValue);
}
accumulator[key] = returnableValue;
return accumulator;
}, {});
}
Problem before I was returning return accumulator[key] = returnableValue, which worked out to be return returnableValue.

Search a value inside complex object

I have a complex object with nested values. Values could be strings, arrays, arrays of objects or null objects. Something like this:
{
foo:'a',
bar:'b',
otherthings : [{yep:'0',yuk:'yoyo0'},{yep:'1',yuk:'yoyo1'}],
foobar : 'yup',
value: null
}
What is the fastest way to check if a value (e.g. yoyo1) exists somewhere in the object? Is there a Javascript built-in function?
Some short iteration:
var data = {
foo: 'a',
bar: 'b',
otherthings: [{ yep: '0', yuk: 'yoyo0' }, { yep: '1', yuk: 'yoyo1' }],
foobar: 'yup',
value: null
};
function findInObject(o, f) {
return Object.keys(o).some(function (a) {
if (Array.isArray(o[a]) || typeof o[a] === 'object' && o[a] !== null) {
return findInObject(o[a], f);
}
return o[a] === f;
});
}
document.write(findInObject(data, 'yoyo1') + '<br>');
document.write(findInObject(data, 'yoyo2') + '<br>');
document.write(findInObject(data, null) + '<br>');
Regex Solution
var myObject = {
foo: 'a',
bar: 'b',
otherthings: [{
yep: '0',
yuk: 'yoyo0'
}, {
yep: '1',
yuk: 'yoyo1'
}],
foobar: 'yup',
value: null
};
var myStringObject = JSON.stringify(myObject);
var matches = myStringObject.match('yep'); //replace yep with your search query
demo
var jsonStr = JSON.stringify(myJSON);
return jsonStr.indexOf(':"yolo1"') !== -1;
This only works if you want to know if it exists (not where it is). It may also not be the most performant.
Another solution:
function findInObject(obj, comparedObj){
return Object.keys(obj).some(function(key){
var value = obj[key];
if (!value) {
return false;
}
if (typeof value === "string") {
return value === comparedObj;
}
if (value instanceof Array) {
return value.some(function(e){
return (typeof value === "string" && e === comparedObj) ||
findInObject(e, comparedObj);
});
}
return findInObject(value, comparedObj);
});
}

How to get the path from javascript object from key and value

I have a javascript object width depth.
I need to know the exact path from this key within the object ex: "obj1.obj2.data1"
I already know the key is data1, the value is 123.
My javascript object look like this
{
obj1: {
obj2: {
data1: 213,
data2: "1231",
obj3: {
data: "milf"
}
}
},
obj4: {
description: "toto"
}
}
How could I achieve that ?
here is a jsfiddle : http://jsfiddle.net/3hvav8xf/8/
I am trying to implement getPath.
I think recursive function can help to you (Updated version, to check value)
function path(c, name, v, currentPath, t){
var currentPath = currentPath || "root";
for(var i in c){
if(i == name && c[i] == v){
t = currentPath;
}
else if(typeof c[i] == "object"){
return path(c[i], name, v, currentPath + "." + i);
}
}
return t + "." + name;
};
console.log(path({1: 2, s: 5, 2: {3: {2: {s: 1, p: 2}}}}, "s", 1));
The following finds the path in any level of nested objects. Also with arrays.
It returns all the paths found, which is something you want if you have keys with the same name.
I like this approach because it works with lodash methods get and set out-of-the-box.
function findPathsToKey(options) {
let results = [];
(function findKey({
key,
obj,
pathToKey,
}) {
const oldPath = `${pathToKey ? pathToKey + "." : ""}`;
if (obj.hasOwnProperty(key)) {
results.push(`${oldPath}${key}`);
return;
}
if (obj !== null && typeof obj === "object" && !Array.isArray(obj)) {
for (const k in obj) {
if (obj.hasOwnProperty(k)) {
if (Array.isArray(obj[k])) {
for (let j = 0; j < obj[k].length; j++) {
findKey({
obj: obj[k][j],
key,
pathToKey: `${oldPath}${k}[${j}]`,
});
}
}
if (obj[k] !== null && typeof obj[k] === "object") {
findKey({
obj: obj[k],
key,
pathToKey: `${oldPath}${k}`,
});
}
}
}
}
})(options);
return results;
}
findPathsToKey({ obj: objWithDuplicates, key: "d" })
// ["parentKey.arr[0].c.d", "parentKey.arr[1].c.d", "parentKey.arr[2].c.d"]
Try it here - https://jsfiddle.net/spuhb8v7/1/
If you want the result to be a single key (first encountered), you can change the results to be a string and if defined, then return the function with it.
I ended up with the following function, that works with nested objects/arrays :
function findPath (obj, name, val, currentPath) {
currentPath = currentPath || ''
let matchingPath
if (!obj || typeof obj !== 'object') return
if (obj[name] === val) return `${currentPath}['${name}']`
for (const key of Object.keys(obj)) {
if (key === name && obj[key] === val) {
matchingPath = currentPath
} else {
matchingPath = findPath(obj[key], name, val, `${currentPath}['${key}']`)
}
if (matchingPath) break
}
return matchingPath
}
const treeData = [{
id: 1,
children: [{
id: 2
}]
}, {
id: 3,
children: [{
id: 4,
children: [{
id: 5
}]
}]
}]
console.log(findPath (treeData, 'id', 5))
Here you go!
function getPath(obj, value, path) {
if(typeof obj !== 'object') {
return;
}
for(var key in obj) {
if(obj.hasOwnProperty(key)) {
console.log(key);
var t = path;
var v = obj[key];
if(!path) {
path = key;
}
else {
path = path + '.' + key;
}
if(v === value) {
return path;
}
else if(typeof v !== 'object'){
path = t;
}
var res = getPath(v, value, path);
if(res) {
return res;
}
}
}
}
getPath(yourObject, valueYouWantToFindPath);
Rerutns path if found, else returns undefined.
I have only tested it with objects & comparison is very strict(ie: used ===).
Update:
Updated version that takes key as an argument.
function getPath(obj, key, value, path) {
if(typeof obj !== 'object') {
return;
}
for(var k in obj) {
if(obj.hasOwnProperty(k)) {
console.log(k);
var t = path;
var v = obj[k];
if(!path) {
path = k;
}
else {
path = path + '.' + k;
}
if(v === value) {
if(key === k) {
return path;
}
else {
path = t;
}
}
else if(typeof v !== 'object'){
path = t;
}
var res = getPath(v, key, value, path);
if(res) {
return res;
}
}
}
}
getPath(yourObject, key, valueYouWantToFindPath);
JSON Object can be handled in JavaScript as associative array.
So You can cycle through and store indexes of "parents" in some variables.
Assume the whole object to be stored in variable called obj.
for( var p1 in obj )
{
for( var p2 in obj[ p1 ] )
{
for( var p3 in obj[ p1 ][ p2 ] )
{
// obj[ p1 ][ p2 ][ p3 ] is current node
// so for Your example it is obj.obj1.obj2.data1
}
}
}
Hope answer was helpful.
I would do this job as follows;
Object.prototype.paths = function(root = [], result = {}) {
var ok = Object.keys(this);
return ok.reduce((res,key) => { var path = root.concat(key);
typeof this[key] === "object" &&
this[key] !== null ? this[key].paths(path,res)
: res[this[key]] == 0 || res[this[key]] ? res[this[key]].push(path)
: res[this[key]] = [path];
return res;
},result);
};
var myObj = {
obj1: {
obj2: {
data1: 213,
data2: "1231",
obj3: {
data: "milf"
}
}
},
obj4: {
description: "toto",
cougars: "Jodi",
category: "milf"
}
},
value = "milf",
milfPath = myObj.paths()[value]; // the value can be set dynamically and if exists it's path will be listed.
console.log(milfPath);
A few words of warning: We should be cautious when playing with the Object prototype. Our modification should have the descriptor enumerable = false or it will list in the for in loops and for instance jQuery will not work. (this is how silly jQuery is, since apparently they are not making a hasOwnProperty check in their for in loops) Some good reads are here and here So we have to add this Object method with Object.defineProperty() to make it enumerable = false;. But for the sake of simplicity and to stay in the scope of the question i haven't included that part in the code.
Here is a pretty short, and relatively easy to understand function I wrote for retrieving the JSON Path for every property/field on an Object (no matter how deeply nested, or not).
The getPaths(object) function just takes the Object you'd like the JSON Paths for and returns an array of paths. OR, if you would like the initial object to be denoted with a symbol that is different from the standard JSON Path symbol, $, you can call getPaths(object, path), and each JSON Path will begin with the specified path.
For Example: getPaths({prop: "string"}, 'obj'); would return the following JSON Path: obj.prop, rather than $.prop.
See below for a more detailed, in depth example of what getPaths returns, and how it is used.
object = {
"firstName": "John",
"lastName": "doe",
"age": 26,
"fakeData": true,
"address": {
"streetAddress": "fake street",
"city": "fake city",
"postalCode": "12345"
},
"phoneNumbers": [{
"type": "iPhone",
"number": "0123-4567-8888"
}, {
"type": "home",
"number": "0123-4567-8910"
}]
};
function getPaths(object, path = "$") {
return Object.entries(object).flatMap(function(o, i) {
if (typeof o[1] === "object" && !o[1].length) {
return `${getPaths(o[1], path + '.' + o[0])}`.split(',');
} else if (typeof o[1] === "object" && o[1].length) {
return Object.entries(o[1]).flatMap((no, i) => getPaths(no[1], `${path}.${o[0]}[${i}]`));
} else {
return `${path}.${o[0]}`;
}
});
}
console.log(`%o`, getPaths(object));
I really liked Roland Jegorov's answer, but I had a very complex object that I needed to search through and that answer could not account for it.
If you were in a situation like mine you may want to first make sure you have no circular references (or else you'll run into an infinite search). There are a few ways to do this, but I was having to stringify my object to copy it into other windows, so I ended up using this circular replacer: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Errors/Cyclic_object_value
(Update here - I made a small change to the getCircularReplacer function from MDN so it no longer leaves out function references since that is what I was looking for!)
(Update 3 - I also wanted to check on methods of any instances of classes, but I was returning just 'function' too early, so I have adjusted it to include instance methods. I think it finally works as I intended!)
const getCircularReplacer = () => {
const seen = new WeakSet();
return (key, value) => {
if (typeof value === "function") {
if (value?.prototype) {
if (seen.has(value.prototype)) {
return;
}
seen.add(value.prototype)
return value.prototype
}
return "function";
}
if (typeof value === "object" && value !== null) {
if (seen.has(value)) {
return;
}
seen.add(value);
}
return value;
};
};
const nonCyclicObject = JSON.parse(JSON.stringify(myComplexObject, getCircularReplacer()));
Then I used this modified version of Roland's answer:
(Update 2: I had to make sure not to return after the key was found as it would always simply return after only calling the function once if the first level of the object had that key)
function findPathsToKey(options) {
let count = 0;
let results = [];
(function findKey({
key,
obj,
pathToKey,
}) {
count += 1;
if (obj === null) return;
const oldPath = `${pathToKey ? pathToKey + "." : ""}`;
if (Object.hasOwnProperty.call(obj, key)) {
results.push(`${oldPath}${key}`);
}
if (typeof obj === "object" && !Array.isArray(obj)) {
for (const k in obj) {
if (Object.hasOwnProperty.call(obj, k)) {
if (Array.isArray(obj[k])) {
for (let j = 0; j < obj[k].length; j++) {
findKey({
obj: obj[k][j],
key,
pathToKey: `${oldPath}${k}[${j}]`,
});
}
}
if (typeof obj[k] === "object") {
findKey({
obj: obj[k],
key,
pathToKey: `${oldPath}${k}`,
});
}
}
}
}
})(options);
return { count, results };
};
The count was just to troubleshoot a little bit and make sure it was actually running through the amount of keys I thought it was. Hope this helps any others looking for a solution!
⚠️ This code doesn't answer the question but does related: transforms nested object to query object with dot.divided.path as keys and non-object values; compatible with URlSearchParams & qs. Maybe will be useful for someone.
const isPlainObject = (v) => {
if (Object.prototype.toString.call(v) !== '[object Object]') return false;
const prototype = Object.getPrototypeOf(v);
return prototype === null || prototype === Object.prototype;
};
const objectToQueryObject = (obj, path) => {
return Object.entries(obj).reduce((acc, [key, value]) => {
const newPath = path ? `${path}.${key}` : key;
if (isPlainObject(value)) {
return {
...acc,
...objectToQueryObject(value, newPath)
};
}
acc[newPath] = value;
return acc;
}, {})
};
const queryObjectRaw = {
value: {
field: {
array: {
'[*]': {
field2: {
eq: 'foo',
ne: 'bar',
}
}
},
someOtherProp: { in: [1, 2, 3],
ne: 'baz',
}
},
someOtherField: {
gt: 123
},
},
otherValue: {
eq: 2
},
};
const result = objectToQueryObject(queryObjectRaw);
console.log('result', result);
const queryString = new URLSearchParams(result).toString();
console.log('queryString', queryString);
If you know only the value and not the key, and want to find all paths with this value use this.
It will find all property with that value, and print the complete path for every founded value.
const createArrayOfKeys = (obj, value) => {
const result = []
function iter(o) {
Object.keys(o).forEach(function(k) {
if (o[k] !== null && typeof o[k] === 'object') {
iter(o[k])
return
}
if (o[k]=== value) {
result.push(k)
return
}
})
}
iter(obj)
return result
}
function findPath (obj, name, val, currentPath) {
currentPath = currentPath || ''
let matchingPath
if (!obj || typeof obj !== 'object') return
if (obj[name] === val) return `${currentPath}/${name}/${val}`
for (const key of Object.keys(obj)) {
if (key === name && obj[key] === val) {
matchingPath = currentPath
} else {
matchingPath = findPath(obj[key], name, val, `${currentPath}/${key}`)
}
if (matchingPath) break
}
return matchingPath
}
const searchMultiplePaths = (obj, value) => {
const keys = createArrayOfKeys(obj, value)
console.log(keys);
keys.forEach(key => {
console.log(findPath(obj, key, value))
})
}
var data = { ffs: false, customer: { customer_id: 1544248, z_cx_id: '123456' }, selected_items: { '3600196': [{ id: 4122652, name: 'Essential Large (up to 8\'x10\')', selected: true }] }, service_partner: { id: 3486, name: 'Some String', street: '1234 King St.', hop: '123456' }, subject: 'Project-2810191 - Orange Juice Stain (Rug)', description: 'Product Type: \n\nIssue: (copy/paste service request details here)\n\nAction Required:', yes: '123456' };
searchMultiplePaths(data, '123456')
I know the post is old but the answers don't really satisfy me.
A simple solution is to add the object path to each object in the structure. Then you can easily read the path when you need it.
let myObject = {
name: 'abc',
arrayWithObject: [
{
name: "def"
},
{
name: "ghi",
obj: {
name: "jkl"
}
}
],
array: [15, 'mno'],
arrayArrayObject: [
[
{
name: '...'
}
]
]
}
function addPath(obj, path = [], objectPathKey = '_path') {
if (Array.isArray(obj)) {
obj.map((item, idx) => addPath(item, [...path, idx]))
} else if (typeof obj === "object") {
obj[objectPathKey] = path;
for (const key in obj) {
obj[key] = addPath(obj[key], [...path, key])
}
}
return obj
}
myObject = addPath(myObject);
let changeMe = _.cloneDeep(myObject.arrayWithObject[0])
changeMe.newProp = "NEW"
changeMe.newNested = {name: "new", deeper: {name: "asdasda"}}
changeMe = addPath(changeMe, changeMe._path)
_.set(myObject, changeMe._path, changeMe);
When your updates are done sanitize your object and remove your _path property.
Advantages of this solution:
You do the work once
you keep your code simple
no need for own property checks
no cognitive overload
I can highly suggest you to use lodash for this problem.
In their documentation this should help you out
// using "_.where" callback shorthand
_.find(characters, { 'age': 1 });
// → { 'name': 'pebbles', 'age': 1, 'blocked': false }

formatting json data to be camelCased

I get a json response from the server that looks something like this:
{
"Response": {
"FirstName": "John",
"LastName": "Smith",
"NickNames": {
"NameOne": "Johnny",
"NameTwo": "JohnS",
"NameThree": "Smithy"
},
"Success": true,
"Errors": []
}
}
Is there a way I can run this response through a function so that the key of each key value pair would be camelCased?
So the output would look something like:
{
"response": {
"firstName": "John",
"lastName": "Smith",
"nickNames": {
"nameOne": "Johnny",
"nameTwo": "JohnS",
"nameThree": "Smithy"
},
"success": true,
"errors": []
}
}
If someone could point me in the right direction, that'd be great.
Thanks.
You would give JSON.parse a reviver function that assigns values to new properties that are lower-cased.
function toCamelCase(key, value) {
if (value && typeof value === 'object'){
for (var k in value) {
if (/^[A-Z]/.test(k) && Object.hasOwnProperty.call(value, k)) {
value[k.charAt(0).toLowerCase() + k.substring(1)] = value[k];
delete value[k];
}
}
}
return value;
}
var parsed = JSON.parse(myjson, toCamelCase);
More information about how it works in this SO answer.
The approach that user '#I Hate Lazy' suggested - using a 'reviver' function is - the right one. However his function didn't work for me.
Perhaps it is because I'm parsing a JSON array. Also I use Resharper and it complained about a code smell :) ('not all code paths return a value'). So I ended up using a function from another SO issue which did work for me:
function camelCaseReviver(key, value) {
if (value && typeof value === 'object') {
for (var k in value) {
if (/^[A-Z]/.test(k) && Object.hasOwnProperty.call(value, k)) {
value[k.charAt(0).toLowerCase() + k.substring(1)] = value[k];
delete value[k];
}
}
}
return value;
}
Here is a functional recursive (ES6) approach.
function convertKeysToCamelCase(o) {
if (o === null || o === undefined) {
return o;
} else if (Array.isArray(o)) {
return o.map(convertKeysToCamelCase);
}
return typeof o !== 'object' ? o : Object.keys(o).reduce((prev, current) => {
const newKey = `${current[0].toLowerCase()}${current.slice(1)}`;
if (typeof o[current] === 'object') {
prev[newKey] = convertKeysToCamelCase(o[current]);
} else {
prev[newKey] = o[current];
}
return prev;
}, {});
}
// successfully tested input
const o = {
SomeNum: 1,
SomeStr: 'a',
SomeNull: null,
SomeUndefined: undefined,
SomeBoolean: true,
SomeNaN: NaN,
NestedObject: {
SomeSentence: 'A is for apple',
AnotherNested: {
B: 'is for blahblah'
}
},
NumArray: [1, 2, 3, 4],
StringArray: ['a', 'b', 'c'],
BooleanArray: [true, false],
ArrayOfArrays: [[1,2,], ['a','b']],
ObjectArray: [{Foo:'bar'}, {Hello:'world', Nested:{In:'deep'}}],
MixedArray: [1,'a', true, null, undefined, NaN, [{Foo:'bar'}, 'wat']]
}
const output = convertKeysToCamelCase(o);
console.log(output.mixedArray[6][0].foo); // 'bar'
#adamjyee Your solution works except for nested array of integers. A small fix could be:
function convertKeysToCamelCase (o) {
if (o === null) {
return null
} else if (o === undefined) {
return undefined
} else if (typeof o === 'number') {
return o
} else if (Array.isArray(o)) {
return o.map(convertKeysToCamelCase)
}
return Object.keys(o).reduce((prev, current) => {
const newKey = `${current[0].toLowerCase()}${current.slice(1)}`
if (typeof o[current] === 'object') {
prev[newKey] = convertKeysToCamelCase(o[current])
} else {
prev[newKey] = o[current]
}
return prev
}, {})
[Right to comment but lacking comment priviledge :(]
You need to write a recursive function that traverses the tree and returns a new tree where the keys in the objects have been updated. The recursive function would call itself to deal with any sub-objects it encounters.

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