Develop Reference

Get object values without using Object.values()

I just started learning to code and am working on this challenge. Having issues finding any relevant guidance online. Thanks in advance.
function keys(json) {
var obj = JSON.parse(json);
let result = [];
for (const key in obj) {
result.push(key);
}
return result;
}
I got this to work for returning keys without using Object.keys and I sort of assumed I could just swap the 'key' for 'value' but that didn't work.
function keys(json) {
var obj = JSON.parse(json);
var values = Object.keys(obj).map((key,value)=>{ values.push(value) });
return values;
}
Also tried this, but I don't really understand the map function yet.

Is this what you are looking for?
const obj = {a:3, b:4}
const result = []
for (const key in obj) {
result.push(obj[key])
}
console.log(result)

With Object.keys you get an array of keys (own, enummerable) of the array. for mapping values, you need to take a property accessor with object and key.
function values(json) {
const object = JSON.parse(json);
return Object
.keys(object)
.map(key => object[key]);
}
console.log(values('{"foo":"bar","baz":42}'));

reactJS adding a object array to and object within an object array

I got a response from a REST call, which returns and array with objects
response.data.steps
For example it looks like this
Now I need to add to each Child of this array an new Object Array.
What could be a smart solution for this problem?
Thanks.

In order to add a new array property to each item, you can simply do:
const steps = response.data.steps.map(step => ({
...step,
newObjectArray: [],
}))

you can usee Array.prototype.map() to do so
let result = response.data.steps.map(element => {
let ret = [element];
return ret;
});
let arr = [{a:1}, {a:2}, {a:3}];
arr = arr.map(element => {
let ret = [element];
return ret;
});
console.log(arr);

Concatenate Object values

I have a JavaScript Object and I'm sure the value of any key is an array (even empty in some case):
{key1:["a","b","c"],key2:["d","e","f"],key3:...}
Aside from using Underscore, is there any way to concatenate all the values of this Object (and create a new array)?
At the moment I get the keys name using Object.keys, then I loop and concatenate.
Any help is appreciated.

var obj = {key1:["a","b","c"],key2:["d","e","f"]};
var arr = Object.keys(obj).reduce(function(res, v) {
return res.concat(obj[v]);
}, []);
// ["a", "b", "c", "d", "e", "f"]

A simple approach is to get the values using Object.values() and concatenate them with [].concat.apply() in this way:
const _obj = { key1:["a","b","c"], key2:["d","e","f"], key3:["g","h","i"] }
const _arr = [].concat.apply([], Object.values(_obj))
console.log(_arr)
Another similar way, is to merge Object.values() by spreading them into Array.concat() like this:
const _obj = { key1:["a","b","c"], key2:["d","e","f"], key3:["g","h","i"] }
const _arr = [].concat(...Object.values(_obj))
console.log(_arr)
Also reducing each value of the Object.values() and concatenate them, you can get the same result:
const _obj = { key1:["a","b","c"], key2:["d","e","f"], key3:["g","h","i"] }
const _arr = Object.values(_obj).reduce((r,c) => r.concat(c), [])
console.log(_arr)
To finish, you can also use Array.prototype.flat() over each value of the Object.values(). Just keep in mind: it's not supported on all browsers.
const _obj = { key1:["a","b","c"], key2:["d","e","f"], key3:["g","h","i"] }
const _arr = Object.values(_obj).flat()
console.log(_arr)
Hope this methods could help someone out there :)

Check the array concat function
var obj = {key1:["a","b","c"],key2:["d","e","f"],key3:["g","h"]};
var resultArray = [];
for (var key in obj) resultArray = resultArray.concat(obj[key]);
alert(resultArray);
jsfiddle:
http://jsfiddle.net/qpLq11ea/

Try this:
http://jsfiddle.net/6hbp5bzo/
var arr= [];
var o={key1:["a","b","c"],key2:["d","e","f"]}
for(key in o){
if(o.hasOwnProperty(key)){
arr.push(o[key]);
}
}
alert(arr);

Returning only certain properties from an array of objects in Javascript [duplicate]

This question already has answers here:
From an array of objects, extract value of a property as array
(24 answers)
Closed 8 years ago.
If I have an object such that
var object = function(key,text)
{
this.key = key;
this.text = text;
}
And create an array of these objects
var objArray = [];
objArray[0] = new object('key1','blank');
objArray[1] = new object('key2','exampletext');
objArray[2] = new object('key3','moretext');
is there a way that I can retrieve only one of the properties of all of the objects in the array? For example:
var keyArray = objArray["key"];
The above example doesn't return set keyArray to anything, but I was hoping it would be set to something like this:
keyArray = [
'key1',
'key2',
'key3']
Does anyone know of a way to do this without iterating through the objArray and manually copying each key property to the key array?

This is easily done with the Array.prototype.map() function:
var keyArray = objArray.map(function(item) { return item["key"]; });
If you are going to do this often, you could write a function that abstracts away the map:
function pluck(array, key) {
return array.map(function(item) { return item[key]; });
}
In fact, the Underscore library has a built-in function called pluck that does exactly that.

var object = function(key,text) {
this.key = key;
this.text = text;
}
var objArray = [];
objArray[0] = new object('key1','blank');
objArray[1] = new object('key2','exampletext');
objArray[2] = new object('key3','moretext');
var keys = objArray.map(function(o,i) {
return o.key;
});
console.log(keys); // ["key1", "key2", "key3"]
JS Bin Example
http://jsbin.com/vamey/1/edit
Note that older browsers may not support map but you can easily do this with a for loop:
var keys = [];
for (var i = 0; i < objArray.length; i++) {
keys.push(objArray[i].key);
}
JS Bin Example
http://jsbin.com/redis/1/edit

You would want to do something like this:
objArray.map(function (obj) { return obj.key; });
Here is a JSFiddle to demo: http://jsfiddle.net/Q7Cb3/
If you need older browser support, you can use your own method:
JSFiddle demo: http://jsfiddle.net/Q7Cb3/1/
function map (arr, func) {
var i = arr.length;
arr = arr.slice();
while (i--) arr[i] = func(arr[i]);
return arr;
}

Well something has to iterate through the elements of the array. You can use .map() to make it look nice:
var keys = objArray.map(function(o) { return o.key; });
You could make a function to generate a function to retrieve a particular key:
function plucker(prop) {
return function(o) {
return o[prop];
};
}
Then:
var keys = objArray.map(plucker("key"));

Really "objArray" is an array that have 3 objects inside, if you want list of keys, you can try this:
var keys = [];
for(a in objArray) {
keys.push(objArray[a].key);
}
You have in var keys, the three keys.
Hope that helps! :)

Javascript: Convert Array to Object

Which is the easiest way to convert this:
[{src:"websrv1"}, {dst:"websrv2"}, {dstport:"80"}]
to this:
{src:"websrv1", dst:"websrv2", dstport:"80"}
in order to pass it to AJAX data?
I'm using VisualSearch and it returns an array of Facet model instances which i need to convert into an Object.

var a = [{src:"websrv1"}, {dst:"websrv2"}, {dstport:"80"}];
var b = a.reduce(
function(reduced,next){
Object.keys(next).forEach(function(key){reduced[key]=next[key];});
return reduced;
}
);
//b should be {src:"websrv1", dst:"websrv2", dstport:"80"}
think about the array.reduce function everytime you need to perform these kind of transformations.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/Reduce

If you are using jquery, try this:
var array = [{src:"websrv1"}, {dst:"websrv2"}, {dstport:"80"}]
var arrayObj = {};
for(var i in array) {
$.extend(arrayObj, array[i]);
}

Use .reduce().
var result = data.reduce(function(obj, item) {
for (var key in item)
obj[key] = item[key];
return obj;
}, {});

Don't use this! but just for fun
var a = [{src:"websrv1"}, {dst:"websrv2"}, {dstport:"80"}];
var f = a.reduce((c,d) => Object.assign(c,d), {})
The tiny drawback is that a is mutated with an infinite recursive object but, who cares? it works in one line!

My 2cents, very easy to read:
var myObj = {};
myArray.forEach(function(obj) {
var prop = Object.keys(obj)[0];
myObj[prop] = obj[prop];
})

Original answer using only the most basic features of JavaScript:
var input = [{src:"websrv1"}, {dst:"websrv2"}, {dstport:"80"}];
var output = {};
for (var i = 0; i < input.length; i++) {
for (var n in input[i]) {
output[n] = input[i][n];
}
}
console.log(output);
UPDATE: Using newer features of JavaScript, you can do this trivially with Object.assign and spread syntax (...):
var input = [{src:"websrv1"}, {dst:"websrv2"}, {dstport:"80"}];
var output = Object.assign({}, ...input);
console.log(output);
Also, Object.assign(...input) will return the same result, but will modify the first element of the input array. As long as you don't mind that side effect, I'd use this simpler version.