Develop Reference

How can i get key of nested object = used For....in?

Here is my code. How can i get the key of the key-value pair using for loop?
var apartment = {
bedroom: {
area: 20,
bed: {
type: 'twin-bed',
price: 100
}
}
};
The desired output is as follows:
/* desired results :
* bedroom
* area
* bed
* type
* price
*/
Please help

var getKeys = function(obj) {
var keys = [];
Object.keys(obj).forEach(function(key){
keys.push(key);
if(typeof obj[key] == 'object'){
keys = keys.concat(getKeys(obj[key]));
}
})
return keys;
}
Then
var keys = getKeys(apartment);

You can use a simple Regex as follow:
var apartment = {
bedroom: {
area: 20,
bed: {
type: 'twin-bed',
price: 100
}
}
};
let result = [];
let jsonstr = JSON.stringify(apartment);
// {"bedroom":{"area":20,"bed":{"type":"twin-bed","price":100}}}
let regex = /"(\w+)":/g;
jsonstr.replace(regex, function(match,prop){
result.push(prop);
});
console.log(result);

we can easily done by using regex, convert object string and apply regex to extract the particular word
run the snippet for required output
var apartment = {
bedroom: {
area: 20,
bed: {
type: 'twin-bed',
price: 100
}
}
};
apartment = JSON.stringify(apartment);
var re = /(")\w+(")(:)/g;
var match;
do {
match = re.exec(apartment);
if (match) {
console.log(match[0]);
}
} while (match);
regex : /(")\w+(")(:)/g
only extracts key for more click here
do while loop responsible to detect multiple match in the string

You can use a recursive function :
function getKeys(source, dest) {
for (let key in source) {
if (typeof source[key] == 'object') {
dest.push(key)
getKeys(source[key], dest)
} else {
dest.push(key)
}
}
return dest
}
result = []
const apartment = {
bedroom: {
area: 20,
bed: {
type: 'twin-bed',
price: 100
}
}
}
getKeys(apartment, result) // ["bedroom", "area", "bed", "type", "price"]

var inputs = [
{a:1,b:2,c:3}, // Simple object
{a:{b:2,c:3}}, // Simple object with nesting
{a:{a:{b:2,c:3}}}, // Repeated key hiding nesting
{a:[{b:2,c:3}]}, // keys behind array
];
inputs.push(inputs); // reference cycle and array at top
function getKeys(obj) {
var all = {};
var seen = [];
checkValue(obj);
return Object.keys(all);
function checkValue(value) {
if (Array.isArray(value)) return checkArray(value);
if (value instanceof Object) return checkObject(value);
}
function checkArray(array) {
if (seen.indexOf(array) >= 0) return;
seen.push(array);
for (var i = 0, l = array.length; i < l; i++) {
checkValue(array[i]);
}
}
function checkObject(obj) {
if (seen.indexOf(obj) >= 0) return;
seen.push(obj);
var keys = Object.keys(obj);
for (var i = 0, l = keys.length; i < l; i++) {
var key = keys[i];
all[key] = true;
checkValue(obj[key]);
}
}
}
var result = inputs.map(getKeys);
console.log(result);

How do I write a function that takes an array of values and returns an object

in this format; sample input: ["book", 1, "table", 4] sample output: { string: ["book", "table"], number: [1,4] }
here is the code i have written but it's not giving me the output i want.
function listDic(arr) {
if (Array.isArray(arr)) {
let output = {};
for (let i =0; i == arr.length; i++) {
if (typeof arr[i] === 'string') {
var str = [];
str.push(arr[i]);
}
if (typeof arr[i] === 'number') {
var num = [];
num.push(arr[i]);
}
}
return {string: str, number: num}
}
return "Only arrays are allowed.";
}
please what exactly am i getting wrong?

You could use the type directly as key for the object, while iterating the array.
If you have not an object with the key, generate a new one with an empty array for pushing the actual item.
var array = ["book", 1, "table", 4],
object = {};
array.forEach(function (a) {
var type = typeof a;
object[type] = object[type] || [];
object[type].push(a);
});
console.log(object);

You're overwriting str and num in the loop without ever keeping any other reference to the arrays. Put those arrays in the output object, and then push into those.
var data = ["book", 1, "table", 4];
console.log(listDic(data));
function listDic(arr) {
if (!Array.isArray(arr)) {
return "Only arrays are allowed.";
}
let output = {
string: [],
number: []
};
for (let i = 0; i < arr.length; i++) {
switch (typeof arr[i]) {
case "string":
output.string.push(arr[i]);
break;
case 'number':
output.number.push(arr[i]);
}
}
return output;
}

You could just reduce the array into an object, and use the type of the values as keys
var arr = ["book", 1, "table", 4];
function listDic(arr) {
return arr.reduce((a, b) => {
let t = typeof b;
a[t] ? a[t].push(b) : a[t] = [b];
return a;
}, {});
}
console.log(listDic(arr));

thanks i got a better way to solve it myself
function listDic(arr) {
if (Array.isArray(arr)) {
let str = [];
let num = [];
for (let i =0; i < arr.length; i++) {
if (typeof arr[i] === 'string') {
str.push(arr[i]);
}
if (typeof arr[i] === 'number') {
num.push(arr[i]);
}
}
return {string: str, number: num}
}
return "Only arrays are allowed.";
}

I think this should work for you :
function listDic(arr) {
if (Array.isArray(arr)) {
let output = {};
var str = [],
num = []; //CORRECTED
for (let i = 0; i < arr.length; i++) { //CORRECTED
if (typeof arr[i] === 'string') {
str.push(arr[i]);
}
if (typeof arr[i] === 'number') {
num.push(arr[i]);
}
}
return { string: str, number: num }
}
return "Only arrays are allowed.";
}
console.log(listDic(["book", 1, "table", 4]));
Explanation
Basically, there were two issues:
you were really not entering the loop with == arr.length on your for-loop's entry condition.
you kept re-assigning the str and num arrays with a re-declaration var str[i] = [] OR var num[i] = [].
Hope this helps.

Generate a nested object structure by string key/path

I want to make a function called createAssociativeArray which will recive two parameters: string and object, like this:
function createAssociativeArray(string, object) {
//...
}
The last item of string should get the object data. See an use/return example:
createAssociativeArray('key1.key2.key3', {
data1: 1,
data2: 2,
data3: 3
});
// key1: {
// key2: {
// key3: {
// data1: 1,
// data2: 2,
// data3: 3
// }
// }
// }
What's the most simple and robust method to do it?
Use eval isn't is a possibility.
What I was tried:
function createAssociativeArray(string, object) {
string = string.split('.');
return string.reduce(function(_object, _target, i) {
_object[_target] = (i + 1 === string.length ? object : {});
return _object;
}, {});
}
It didn't produced the expected result because the object is reseted to {}.
[JSFiddle]

Here's what I came up with:
function createAssociativeArray(string, object) {
var parts = string.split('.');
var last = parts[parts.length - 1];
var tree = {};
var node = parts.slice(0, -1).reduce(function (memo, current) {
return (memo[current] = {});
}, tree);
node[last] = object;
return tree;
}

I was curious to see if I could make a recursive solution, so here it is:
function createAssociativeArray(string, object) {
if (string === "") return object;
var stringarr = string.split('.');
var laststr = stringarr.pop();
var newobj = {};
newobj[laststr] = object;
return createAssociativeArray(stringarr.join("."), newobj);
}
Working JSFiddle demo: https://jsfiddle.net/pt352dxg/

Possible implementation:
Working demo
function createChain(keys, value) {
var obj = {};
var target = obj;
keys = keys.split('.');
keys.forEach(function(key, index) {
target = target[key] = index === keys.length - 1 ? value : {};
});
target = value;
return obj;
}

This function actually can accept an optional existing Object ({k:2, kk: 3, key1: 4}) and merge that with given json path. e.g. Try on chrome debugger console:
JSON.stringify(createAssociativeArray('key1.key2.key3', { data1: 1, data2: 2, data3: 3}, {k:2,kk:3, key1:{}}))
will print this:
"{"k":2,"kk":3,"key1":{"key2":{"key3":{"data1":1,"data2":2,"data3":3}}}}"
..
function createAssociativeArray(key, value, data) {
if(!finalData && data)
finalData = data;
var finalData;
if (!data)
data = finalData = {};
var keys = key.split('.');
if (keys.length < 2) {
data[keys[0]] = value;
} else {
if (!data[keys[0]])
data[keys[0]] = {};
data = data[keys.shift()];
createAssociativeArray(keys.join("."),value,data);
}
return finalData;
};

You were pretty close in your original attempt.
function createAssociativeArray(string, object) {
return string.split('.').reverse().reduce(function (inner, key) {
var outer = {};
outer[key] = inner;
return outer;
}, object);
}
http://jsfiddle.net/xewoa06t/

This worked for me:
function createAssociativeArray(string, object){
var array = string.split('.');
var aArray = {};
if(array.length > 1){
aArray[array[array.length - 1]] = object;
array.splice(array.length - 1, 1);
createAssociativeArray(array.join('.'), aArray)
}else{
aArray[array[array.length - 1]] = object;
return aArray
}
};
createAssociativeArray('key1.key2.key3', {data1: 1, data2: 2, data3: 3});
Basically, builds object from ground up, starting with the original object, then wrapping the 'layers' around it recursively

Nice case for a recursive function!
function createAssociativeArray(string, object) {
if (string.split('.').length == 1) {
var outObj = {};
outObj[string] = object;
return outObj;
} else {
var outObj = {};
outObj[string.split('.')[0]] = createAssociativeArray(string.split('.').slice(1).join('.'), object);
return outObj;
}
}

It's easier with a simple loop, the key point is doing in reverse (like #JustcallmeDrago)
function createAssociativeArray(keys, data)
{
var temp, keyPart
for(keys = keys.split('.'); keys.length; data = temp)
{
keyPart = keys.pop()
temp = {}
temp[keyPart] = data
}
return data
}
// TEST
x = createAssociativeArray("key1.key2.key3", { data1: "value1", data2: "value2" })
document.write('<pre>'+x+'\n'+x.key1 +'\n'
+x.key1.key2 + '\n'
+x.key1.key2.key3 +'\n'
+x.key1.key2.key3.data1 +'\n'
+x.key1.key2.key3.data2 +'</pre>')

Since no one have proviced a while-loop solution:
function namespace(path, context) {
var obj = context;
var s = path.split('.');
var p;
while (s.length) {
p = s.shift();
obj = obj[p] || (obj[p] = {});
}
return context;
}

ES6 one liner
(str, obj) => str.split('.').reverse().reduce((inner, key) => ({[key]: inner}), obj);

How to convert square bracket object keys from URL location into nested object in Javascript?

With:
var obj = { "object[foo][bar][ya]": 100 };
How can I create:
var obj = { object: { foo: { bar: { ya: 100 }}}};

Manual approach
Split the given string with bracket, then iterate through the resultant tokens to make the nested object:
Given
var obj = { "object[foo][bar][ya]": 100 };
Split them so we get
var tokens = Object.keys(obj)[0]
.split('[')
.map(function(s){return s.replace(']','')});
// tokens = [ 'object', 'foo', 'bar', 'ya' ]
Then make the nested object, inside out
var result = {};
tokens.reverse().forEach(function(key){
if (Object.keys(result).length==0){
result[key] = obj[Object.keys(obj)[0]]; // inner-most key-value
}
else{
var temp = {};
temp[key] = result;
result = temp;
}
});
Result
{"object":{"foo":{"bar":{"ya":100}}}}

Their is no native things in javascript fr parsing nested object in querystring.
You can use http://medialize.github.io/URI.js/ which is pretty damn good at the job.
console.log(URI.parseQuery("?&foo=bar&&foo=bar&foo=baz&"));
If you don't want to import the full library, this is just the part for querystring parsing (full credit to https://github.com/medialize/URI.js):
var URI = {
decodeQuery: function(string, escapeQuerySpace) {
string += '';
try {
return decodeURIComponent(escapeQuerySpace ? string.replace(/\+/g, '%20') : string);
} catch(e) {
// we're not going to mess with weird encodings,
// give up and return the undecoded original string
// see https://github.com/medialize/URI.js/issues/87
// see https://github.com/medialize/URI.js/issues/92
return string;
}
},
parseQuery: function(string, escapeQuerySpace) {
if (!string) {
return {};
}
// throw out the funky business - "?"[name"="value"&"]+
string = string.replace(/&+/g, '&').replace(/^\?*&*|&+$/g, '');
if (!string) {
return {};
}
var items = {};
var splits = string.split('&');
var length = splits.length;
var v, name, value;
for (var i = 0; i < length; i++) {
v = splits[i].split('=');
name = URI.decodeQuery(v.shift(), escapeQuerySpace);
// no "=" is null according to http://dvcs.w3.org/hg/url/raw-file/tip/Overview.html#collect-url-parameters
value = v.length ? URI.decodeQuery(v.join('='), escapeQuerySpace) : null;
if (Object.prototype.hasOwnProperty.call(items, name)) {
if (typeof items[name] === 'string') {
items[name] = [items[name]];
}
items[name].push(value);
} else {
items[name] = value;
}
}
return items;
}
};

You could get the parts and build a new object.
const obj = {
"object[foo][bar][ya]": 100,
"object[foo][baz]": 200,
"object[foo][bar][bar]": 50,
"xy": 30
};
let newObj = {};
for (const i in obj) {
let a = i.match(/([^\[\]]+)(\[[^\[\]]+[^\]])*?/g),
p = obj[i];
j = a.length;
while (j--) {
q = {};
q[a[j]] = p;
p = q;
}
// merge object
let k = Object.keys(p)[0],
o = newObj;
while (k in o) {
p = p[k];
o = o[k];
k = Object.keys(p)[0];
}
o[k] = p[k];
}
console.log(newObj);
.as-console-wrapper { max-height: 100% !important; top: 0; }

Here's an es6 version. Caution: Hasn't been tested for edge cases.
const keyPattern = /^(\w+)\[(\w+)\](.*)$/;
export function decodeParams(params) {
return Object.keys(params).reduce((result, key) => {
let match = key.match(keyPattern);
if (match && match.length >= 3) {
let [key, nextKey, rest = ''] = match.slice(1);
result[key] = Object.assign(
{},
result[key],
decodeParams({ [nextKey + rest]: params[key] })
);
} else {
result[key] = params[key];
}
return result;
}, {});
}

Javascript Recursion for creating a JSON object

needing some advice on how to do this properly recursively.
Basically what I'm doing, is entering in a bunch of text and it returns it as JSON.
For example:
The text:
q
b
name:rawr
Returns:
[
"q",
"b",
{
"name": "rawr"
}
]
And the following input:
q
b
name:rawr:awesome
Would return (output format is not important):
[
"q",
"b",
{
"name": {
"rawr": "awesome"
}
}
]
How can I modify the following code to allow a recursive way to have objects in objects.
var jsonify = function(input){
var listItems = input, myArray = [], end = [], i, item;
var items = listItems.split('\r\n');
// Loop through all the items
for(i = 0; i < items.length; i++){
item = items[i].split(':');
// If there is a value, then split it to create an object
if(item[1] !== undefined){
var obj = {};
obj[item[0]] = item[1];
end.push(obj);
}
else{
end.push(item[0]);
}
}
// return the results
return end;
};

I don't think recursion is the right approach here, a loop could do that as well:
var itemparts = items[i].split(':');
var value = itemparts.pop();
while (itemparts.length) {
var obj = {};
obj[itemparts.pop()] = value;
value = obj;
}
end.push(value);
Of course, as recursion and loops have equivalent might, you can do the same with a recursive function:
function recurse(parts) {
if (parts.length == 1)
return parts[0];
// else
var obj = {};
obj[parts.shift()] = recurse(parts);
return obj;
}
end.push(recurse(items[i].split(':')));

Here is a solution with recursion:
var data = [];
function createJSON(input) {
var rows = input.split("\n");
for(var i = 0; i < rows.length; i++) {
data.push(createObject(rows[i].split(":")));
}
}
function createObject(array) {
if(array.length === 1) {
return array[0];
} else {
var obj = {};
obj[array[0]] = createObject(array.splice(1));
return obj;
}
}
createJSON("p\nq\nname:rawr:awesome");
console.log(data);