We Keep Coding

Javascript test for existence of object key in a object with arrays which use values instead of index

I have been reading through many of the great code examples which test for the existence of object key in a object with arrays. These are great...
My problem is the JSON returned has key value that must be used to get to the items inside the array. Here is an example. Look at "orders":
{"Routes": [
{
"route": {
"id": "1daf1f53-80b6-49d6-847a-0ee8b814e784-20180821"
},
"vehicle": {
"id": "1daf1f53-80b6-49d6-847a-0ee8b814e784"
},
"driver": {
"id": "6c2823be-374e-49e5-9d99-2c3f586fc093"
},
"orders": {
"6df85e5f-c8bc-4290-a544-03d7895526b9": {
"id": "6df85e5f-c8bc-4290-a544-03d7895526b9",
"delivery": {
"customFields": {
"custom": "5379"
}
},
"isService": true
}
}
}
]
};
The code I am using works up to the point where I have to specify the key value:
function checkProperty(obj, prop) {
var parts = prop.split('.');
for (var i = 0, l = parts.length; i < l; i++) {
var part = parts[i];
if (obj !== null && typeof obj === "object" && part in obj) {
obj = obj[part];
} else {
return false;
}
return true;
}
Here are some samples that work and fail:
console.log(checkProperty(test, 'Routes.0.orders')); //Works returns true
console.log(checkProperty(test, 'Routes.0.orders.id')); //Fails returns false
console.log(checkProperty(test, 'Routes.0.orders.6df85e5f-c8bc-4290-a544-03d7895526b9.id)); //Fails returns false
I am at my wits end and would appreciate any help...

"orders": {
"6df85e5f-c8bc-4290-a544-03d7895526b9": {
"id": "6df85e5f-c8bc-4290-a544-03d7895526b9"
second test:
Id is not a direct child of "Orders" in your example:
orders.6df85e5f-c8bc-4290-a544-03d7895526b9.id
third test:
syntax error in the third - missing '.'

How can I remove blank fields from a json?

So I am given a json and I have to clean it up, by removing all the 'blank' fields. The fields that are considered blank are:
empty arrays or objects,
strings with whitespace ("" or " "),
null values.
This is what I have so far:
const isBlank = (val) => {
if(val === null ) {
return true
}
if(typeof val === 'string'){
return val.trim().length === 0;
}
return val.length === 0
};
function clean(jsonInput) {
Object.keys(jsonInput).forEach( key => {
if(typeof jsonInput[key] === 'object' && !isEmpty(jsonInput[key])){
clean(jsonInput[key])
}else {
isEmpty(jsonInput[key_field]) && delete jsonInput[key]
}
})
}
This is the jsonInput I am working with:
{
"print": "notBlank",
"this": "notBlank",
"example": "notBlank",
"blank": null,
"allBlanks": [
{
"from": "",
"blank0": null
}
],
"att2": {
"blank1": "",
"blank2": []
},
"att3": {
"one": "1",
"two": "2",
"three": "3",
"blank3": " "
}
}
This should be the output:
{
"print": "notBlank",
"this": "notBlank",
"example": "notBlank",
"att3": {
"one": "1",
"two": "2",
"three": "3"
}
}
Instead I am getting this:
{
"print": "notBlank",
"this": "notBlank",
"example": "notBlank",
"allBlanks": [{ }],
"att2": {},
"att3": {
"one": "1",
"two": "2",
"three": "3",
}
}
It seams like I am unable to remove the objects... Any ideas what I am doing wrong? Any way I can fix it.
Also is there a way to do this so that I don't change the original object and instead I make a duplicate, maybe with map or filter?

The main issue here is that [{}] was not defined as "empty" because it was an array of length 1 with an object in it. However, because you would like empty objects to be considered empty, and thus arrays with empty objects to be empty, you need to also recurse inside of your isEmpty function to cover these angles.
Note the two recursive calls for arrays and objects added to isEmpty.
As for as copying goes, the quick dirty way would be to first stringify then parse the json. You can see this towards the bottom of the code with the line
var jsonCopy = JSON.parse(JSON.stringify(json));
There are more complex ways of deep copying as well, please read What is the most efficient way to deep clone an object in JavaScript? for more information there.
const isEmpty = (val) => {
if(val === null ) {
return true
}
if(typeof val === 'string'){
return val.trim().length === 0;
}
if(val instanceof Array){
if( val.length === 0 ) return true;
return val.every( v =>
isEmpty(v)
);
}
if(val === Object(val)){
if(Object.keys(val).length == 0) return true;
return Object.values(val).every(
v => isEmpty(v)
);
}
return val.length === 0;
};
function clean(jsonInput) {
Object.keys(jsonInput).forEach( key => {
if(typeof jsonInput[key] === 'object' && !isEmpty(jsonInput[key])){
clean(jsonInput[key])
}else {
isEmpty(jsonInput[key]) && delete jsonInput[key]
}
})
}
var json = {
"print": "notBlank",
"this": "notBlank",
"example": "notBlank",
"blank": null,
"allBlanks": [
{
"from": "",
"blank0": null
}
],
"att2": {
"blank1": "",
"blank2": []
},
"att3": {
"one": "1",
"two": "2",
"three": "3",
"blank3": " "
}
};
var jsonCopy = JSON.parse(JSON.stringify(json));
clean(jsonCopy);
console.log(jsonCopy);

Some features like this already exist in the lodash
https://lodash.com/docs/4.17.10#omitBy
Avoid using delete in javascript, its slow and not a good pratice
Example:
var _ = require("lodash")
var oldObj = {a:1, b:2, c:null, d:"aa"}
var newObj = _.omitBy(oldObj, (value, key) =>
_.isNull(value) ||
(_.isString(value) && _.isEmpty(value)) ||
(_.isArray(value) && _.isEmpty(value)) );
console.log("Final", newObj) //Final { a: 1, b: 2, d: 'aa' }
isEmpty return true if value is a number https://lodash.com/docs/4.17.10#isEmpty
Edit:
The keyword delete throws an exception in strict mode https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/delete

How to access json data property in nodejs

I have a json that is similar to the code below.
var jsonData = {
"Config": {
"AttachStderr": false,
"AttachStdin": false,
"AttachStdout": false,
"CpuShares": 0,
"Cpuset": "",
"Domainname": "",
"Entrypoint": null,
"Env": [
"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
"HOME=/root"
]
"Hostname": "git",
"WorkingDir": ""
},
"Created": "2015-03-03T08:59:05.735601013Z",
"Name": "/git",
"NetworkSettings": {
"Ports": {
"22/tcp": [
{
"HostIp": "0.0.0.0",
"HostPort": "2008"
}
],
"80/tcp": null,
"8006/tcp": [
{
"HostIp": "0.0.0.0",
"HostPort": "9008"
}
]
}
},
"ResolvConfPath": "/etc/resolv.conf",
"State": {
"Pid": 6146,
"Running": true,
"StartedAt": "2015-03-03T08:59:05.829535361Z"
}
}
As you can see any properties has it's own unique name. My question is: How can I access the properties like Env in this way getValue(jsonData, 'Env'); ?
My json is much bigger and more complex than what I put above.

Here's a function that allows you to recurse through an object to find the information you need if you don't know the structure of the object. Note that this will break out of the function when the first instance of that key has been found. This means that if you have more than one key called HostIp, it will only find the first one.
function getValue(obj, key) {
var found = null;
var recurse = function (obj, key) {
for (var p in obj) {
if (p === key) {
found = obj[p];
break;
}
if (obj[p] !== null && typeof obj[p] === 'object') recurse(obj[p], key);
}
}
recurse(obj, key);
return found;
}
getValue(jsonData, 'Env'); // [ "PATH=/usr/local/sbin:/usr/local/bin…", "HOME=/root" ]
If you want to find all instances of a particular key name use the following code instead. It will add all matches to an array and return that array once the object has been trawled. This isn't particularly useful tho because it doesn't provide the context in which it found the key, but it might give you a few ideas.
function getValue(obj, key) {
var found = [];
var recurse = function (obj, key) {
for (var p in obj) {
if (p === key) {
found.push(obj[p]);
}
if (obj[p] !== null && typeof obj[p] === 'object') recurse(obj[p], key);
}
}
recurse(obj, key);
return found;
}
getValue(jsonData, 'HostPort'); // [ "2008", "9008" ]
DEMO

Finding specific child element in JSON

I am trying to display a button, only if a json object contains the element hidden: true
However, the child elements are random.
draw": { "item": { "aircraft": { "hidden": false} }
draw": { "item": { "mounted": { "hidden": false} }
I am ng-repeating on this json, and since I don't know if it is aircraft or mounted I can't do something like this
<button ng-if="json.draw.item.next.hidden" />
How can I say "Give me next element, without knowing the name"?

You can create a function like this:
function next(obj) {
var keys = Object.keys(obj);
if(keys && keys.length > 0) return obj[keys[0]];
}
To use it:
next(json.draw.item).hidden
I test it with Angular.js it is Ok.(see also jsFiddle)
See the snippet below.
function next(obj) {
var keys = Object.keys(obj);
if(keys && keys.length > 0) return obj[keys[0]];
}
var draw1 = { "item": { "aircraft": { "hidden": false} }};
var draw2 = { "item": { "mounted": { "hidden": false} }};
document.write(next(draw1.item).hidden, '<br>');
document.write(next(draw2.item).hidden, '<br>');

how to construct a json object using info from several javascript arrays

I have two js arrays already, say: names and values (with the same length), now I would like to construct a json object in certain format? For example:
names = ["label1","label2","label3"];
values = [[[0,1],[1,9],[2,10]],[[0,89],[1,91],[2,1]],[[0,1],[1,9],[2,10]]];
I would like to have a json array data_spec in this format:
[{
label:"label1",
data:[[0,1],[1,9],[2,10]]
},
{
label:"label2",
data:[[0,89],[1,91],[2,1]]
},
{
label:"label3",
data:[[0,1],[1,9],[2,10]]
}]
Could anyone tell one how? Thanks a lot!

For a bit of variety and a check,
var data_spec = [];
if (names.length != values.length) {
// panic, throw an exception, log an error or just return an empty array
} else {
for (var i=0, name; name = names[i]; i++) { // assuming a non-sparse array
data_spec[i] = {
label : name,
data : values[i]
};
}
}
That is, non-sparse and not containing anything else that would evaluate to false.
If your framework has an each function added to Array and you don't care about performance,
var data_spec = [];
names.each(function(name) {
data_spec.push({ label : name, data : values[names.indexOf(name)] });
});
If your framework is a clean one like Dojo and puts it somewhere else (ex is Dojo),
var data_spec = [];
dojo.forEach(names, function(name) {
data_spec.push({ label : name, data : values[names.indexOf(name)] });
});
If your framework has an each function that returns an Array of identical length with the results of every operation at their expected position,
var data_spec = arrayOfResultsEach(names, function(name) {
return { label : name, data : values[names.indexOf(name)] };
});
These are just for illustration, indexOf inside loops of arbitrary length is a major code smell.

Just use a loop (make sure the two arrays are of same length)
result = [];
for(var i=0, len=names.length; i < len; i++) {
result.push({label: names[i], data: values[i]});
}

var myArray =
[{
"label": "label1",
"data" :
{
"0": "1",
"1": "9",
"2": "10"
}
},
{
"label": "label2",
"data" :
{
"0": "89",
"1": "91",
"2": "1"
}
},
{
"label": "label3",
"data" :
{
"0": "1",
"1": "9",
"2": "10"
}
}];
alert(myArray[0].data[2]);