Dynamically retrieving variable from chained objects

Dynamically retrieving variable from chained objects - javascript

I'm having trouble figuring out how to access a variable in a multilevel deep object using a function like
getLanguageVariable("form.passwordSwitch.disabled");
and the following object as sample
var language = {
"de": {
"form": {
"passwordSwitch": {
"enabled": "Der Klartext-Modus ist aus. Aktivieren?",
"disabled": "Der Klartext-Modus ist an. Deaktivieren?"
}
}
}
}
Tried to split the string at the dot character, then creating a string representation of
language["de"]["form"]["passwordSwitch"]["enabled"]
which is used to access objects and it's properties. I used this code:
var stack = variableIdentifier.split(".");
var reference = "";
for (i = 0; i < stack.length; i++) {
if (i == 0) reference += stack[i];
else reference += "[\"" + stack[i] + "\"]";
}
Any clues how to dynamically access the properites of an object, given you don't know how deep it is?

I implemented the same in pythons a couple of days ago. Basically, When you do not know how deep the object is, use a recursion pattern.
function getPath(obj, path)
{
path = path.split('.');
return _getpath(obj, path);
}
function _getPath(obj, path)
{
if(!path.length)
return obj;
p = path.shift();
if(obj[p])
return _getPath(obj[p], path);
return undefined;
}

You can do something like this;
function getLanguageVariable(path) {
// I don't know how you determine "de", but this should be
// easy to customise
var next = language.de;
// Make path = ["form","passwordSwitch","disabled"];
path = path.split(/\./);
// Loop over path, and for each pass, set next to the next key
// e.g. next = next["form"];
// next = next["passwordSwitch"]
// next = next["disabled"]
while (path.length && (next = next[path.shift()]) && typeof next === "object" && next !== null);
// Check we have used all the keys up (path.length) and return
// either undefined, or the value
return path.length ? undefined : next;
}
For future information, note what you have is an Object defined via Object Literal Syntax, and is not JSON at all; for more info see What is the difference between JSON and Object Literal Notation?

Related

JavaScript callback-function in PHP-Array [duplicate]

I have a JS object I would like to save in Local Storage for future use, and I cannot parse it to a string.
Code:
JSON.stringify({
a: 5,
b: function (param) {
return param;
}
})
Result:
"{"a":5}"
How do I save it for future use, if not with JSON?
(And creating my own Lexer-Parser to interupt string function I dont think is an option)

I'd recommend this approach:
Store arguments and the body in your json:
{"function":{"arguments":"a,b,c","body":"return a*b+c;"}}
Now parse json and instantiate the function:
var f = new Function(function.arguments, function.body);
I think it's save

Usually a question like this indicates an X/Y problem: You need to do X, you think Y will help you do that, so you try to do Y, can't, and ask how to do Y. It would frequently be more useful to ask how to do X instead.
But answering the question asked: You could use replacer and reviver functions to convert the function to a string (during stringify) and back into a function (during parse) to store a string version of the function, but there are all sorts of issues with doing that, not least that the scope in which the function is defined may well matter to the function. (It doesn't matter to the function you've shown in the question, but I assume that's not really representative.) And converting a string from local storage into code you may run means that you are trusting that the local storage content hasn't been corrupted in a malicious way. Granted it's not likely unless the page is already vulnerable to XSS attacks, but it's an issue to keep in mind.
Here's an example, but I don't recommend it unless other options have been exhausted, not least because it uses eval, which (like its close cousin new Function)) can be a vector for malicious code:
// The object
var obj = {
a: 5,
b: function (param) {
return param;
}
};
// Convert to JSON using a replacer function to output
// the string version of a function with /Function(
// in front and )/ at the end.
var json = JSON.stringify(obj, function(key, value) {
if (typeof value === "function") {
return "/Function(" + value.toString() + ")/";
}
return value;
});
// Convert to an object using a reviver function that
// recognizes the /Function(...)/ value and converts it
// into a function via -shudder- `eval`.
var obj2 = JSON.parse(json, function(key, value) {
if (typeof value === "string" &&
value.startsWith("/Function(") &&
value.endsWith(")/")) {
value = value.substring(10, value.length - 2);
return (0, eval)("(" + value + ")");
}
return value;
});
document.body.innerHTML = obj2.b(42);
The construct (0, eval)("(" + value + ")"); ensures that eval runs at global scope rather than within the scope of the reviver function. Normally eval has a magic ability to use the scope you call it in, but that only works when you call it directly. Indirect eval as shown (or just var e = eval; e("(" + value + ")");) doesn't have that magic ability, it runs at global scope.

You can't store functions in JSON.
The value in JSON may contain only string, number, object, array, true, false or null:
Check out it on JSON site.

One simple way of doing this is
var dstr = JSON.stringify( { a: 5
, b: x => x
}
, (k,v) => typeof v === "function" ? "" + v : v
);

I've taken to storing the function name, along with the parameter values, in an array, with the first item in the array being the function name prepended with a $, to separate them from normal arrays.
{
"object": {
"your-function": ["$functionName", "param-1", "param-2"],
"color": ["$getColor", "brand", "brand-2"],
"normal-array": ["normal", "array"]
...
}
}
In the above example I have Sass and JS functions to retrieve color values from a global map/object. Parsing the function in this manner naturally requires custom code, but in terms of "storing" functions in JSON, I like this way of doing it.

I have created JSON.parseIt() and JSON.stringifyIt() functions based on the first answer without using eval
JSON.stringifyIt = (obj)=>{
return(
JSON.stringify(obj, function(key, value) {
if (typeof value === "function") {
return "/Function(" + value.toString() + ")/";
}
if(typeof value === "string"){
return "/String(" + value.toString() + ")/"
}
return value;
})
)
}
JSON.parseIt=(json)=>{
return(
JSON.parse(json, function(key, value) {
if (typeof value === "string" &&
value.startsWith("/Function(") &&
value.endsWith(")/")) {
value = value.substring(10, value.length - 2);
var string = value.slice(value.indexOf("(") + 1, value.indexOf(")"));
if(/\S+/g.test(string)){
return (new Function(string,value.slice(value.indexOf("{") + 1, value.lastIndexOf("}"))))
}else{
return (new Function(value.slice(value.indexOf("{") + 1, value.lastIndexOf("}"))));
}
}
if (typeof value === "string" &&
value.startsWith("/String(") &&
value.endsWith(")/")){
value = value.substring(8, value.length - 2);
}
return value;
})
)
}
// DEMO
var obj = {
string:"a string",
number:10,
func:()=>{
console.log("this is a string from a parsed json function");
},
secFunc:(none,ntwo)=>{console.log(none + ntwo)} ,
confuse:"/Function(hello)/"
}
const stringifiedObj = JSON.stringifyIt(obj);
console.log("the stringified object is: ",stringifiedObj);
const parsedObj = JSON.parseIt(stringifiedObj);
// console.log("the parsed object is: ",parsedObj);
console.log(parsedObj.string);
console.log(parsedObj.number);
console.log(parsedObj.confuse);
parsedObj.func();
parsedObj.secFunc(5,6);
The problems I fixed were
Removed eval.
there was a problem in the stringifying and parsing that if I give a string like
"/Function(hello)/" will be a function when parsed
Made it to two functions
Added parameter insertation

For someone that still need include, for whatever reason, the function definition in JSON, this code can help (but can be slow depending object size):
function Object2JsonWithFunctions(o, space = null) {
var functionList = {}
var fnSeq = 0;
var snrepl = function(k,v){
if(typeof v === 'function'){
fnSeq++;
var funcName = `___fun${fnSeq}___`;
var funcText = ''+v;
functionList[funcName] = funcText
return funcName;
}
return v;
}
var RawJson = JSON.stringify(o, snrepl, space);
for(func in functionList){
var PropValue = `"${func}"`;
RawJson = RawJson.replace(PropValue, functionList[func])
}
return RawJson;}
The code will do the normal convert to JSON.
For functions, the original stringify will return as "prop":"function()..." (function as a string)... The code above will create a placeholder (e.g: "prop":"fn1") and create a function list... After, will replace every placeholder to original function body...

Access sub-property with generic/dynamic property list [duplicate]

I have a bunch of object attributes coming in as dot-delimited strings like "availability_meta.supplier.price", and I need to assign a corresponding value to record['availability_meta']['supplier']['price'] and so on.
Not everything is 3 levels deep: many are only 1 level deep and many are deeper than 3 levels.
Is there a good way to assign this programmatically in Javascript? For example, I need:
["foo.bar.baz", 1] // --> record.foo.bar.baz = 1
["qux.qaz", "abc"] // --> record.qux.qaz = "abc"
["foshizzle", 200] // --> record.foshizzle = 200
I imagine I could hack something together, but I don't have any good algorithm in mind so would appreciate suggestions. I'm using lodash if that's helpful, and open to other libraries that may make quick work of this.
EDIT this is on the backend and run infrequently, so not necessary to optimize for size, speed, etc. In fact code readability would be a plus here for future devs.
EDIT 2 This is NOT the same as the referenced duplicate. Namely, I need to be able to do this assignment multiple times for the same object, and the "duplicate" answer will simply overwrite sub-keys each time. Please reopen!

You mentioned lodash in your question, so I thought I should add their easy object set() and get() functions. Just do something like:
_.set(record, 'availability_meta.supplier.price', 99);
You can read more about it here: https://lodash.com/docs#set
These functions let you do more complex things too, like specify array indexes, etc :)

Something to get you started:
function assignProperty(obj, path, value) {
var props = path.split(".")
, i = 0
, prop;
for(; i < props.length - 1; i++) {
prop = props[i];
obj = obj[prop];
}
obj[props[i]] = value;
}
Assuming:
var arr = ["foo.bar.baz", 1];
You'd call it using:
assignProperty(record, arr[0], arr[1]);
Example: http://jsfiddle.net/x49g5w8L/

What about this?
function convertDotPathToNestedObject(path, value) {
const [last, ...paths] = path.split('.').reverse();
return paths.reduce((acc, el) => ({ [el]: acc }), { [last]: value });
}
convertDotPathToNestedObject('foo.bar.x', 'FooBar')
// { foo: { bar: { x: 'FooBar' } } }

Just do
record['foo.bar.baz'] = 99;
But how would this work? It's strictly for the adventurous with a V8 environment (Chrome or Node harmony), using Object.observe. We observe the the object and capture the addition of new properties. When the "property" foo.bar.baz is added (via an assignment), we detect that this is a dotted property, and transform it into an assignment to record['foo']['bar.baz'] (creating record['foo'] if it does not exist), which in turn is transformed into an assignment to record['foo']['bar']['baz']. It goes like this:
function enable_dot_assignments(changes) {
// Iterate over changes
changes.forEach(function(change) {
// Deconstruct change record.
var object = change.object;
var type = change.type;
var name = change.name;
// Handle only 'add' type changes
if (type !== 'add') return;
// Break the property into segments, and get first one.
var segments = name.split('.');
var first_segment = segments.shift();
// Skip non-dotted property.
if (!segments.length) return;
// If the property doesn't exist, create it as object.
if (!(first_segment in object)) object[first_segment] = {};
var subobject = object[first_segment];
// Ensure subobject also enables dot assignments.
Object.observe(subobject, enable_dot_assignments);
// Set value on subobject using remainder of dot path.
subobject[segments.join('.')] = object[name];
// Make subobject assignments synchronous.
Object.deliverChangeRecords(enable_dot_assignments);
// We don't need the 'a.b' property on the object.
delete object[name];
});
}
Now you can just do
Object.observe(record, enable_dot_assignments);
record['foo.bar.baz'] = 99;
Beware, however, that such assignments will be asynchronous, which may or may not work for you. To solve this, call Object.deliverChangeRecords immediately after the assignment. Or, although not as syntactically pleasing, you could write a helper function, also setting up the observer:
function dot_assignment(object, path, value) {
Object.observe(object, enable_dot_assignments);
object[path] = value;
Object.deliverChangeRecords(enable_dot_assignments);
}
dot_assignment(record, 'foo.bar.baz', 99);

Something like this example perhaps. It will extend a supplied object or create one if it no object is supplied. It is destructive in nature, if you supply keys that already exist in the object, but you can change that if that is not what you want. Uses ECMA5.
/*global console */
/*members split, pop, reduce, trim, forEach, log, stringify */
(function () {
'use strict';
function isObject(arg) {
return arg && typeof arg === 'object';
}
function convertExtend(arr, obj) {
if (!isObject(obj)) {
obj = {};
}
var str = arr[0],
last = obj,
props,
valProp;
if (typeof str === 'string') {
props = str.split('.');
valProp = props.pop();
props.reduce(function (nest, prop) {
prop = prop.trim();
last = nest[prop];
if (!isObject(last)) {
nest[prop] = last = {};
}
return last;
}, obj);
last[valProp] = arr[1];
}
return obj;
}
var x = ['fum'],
y = [
['foo.bar.baz', 1],
['foo.bar.fum', new Date()],
['qux.qaz', 'abc'],
['foshizzle', 200]
],
z = ['qux.qux', null],
record = convertExtend(x);
y.forEach(function (yi) {
convertExtend(yi, record);
});
convertExtend(z, record);
document.body.textContent = JSON.stringify(record, function (key, value, Undefined) {
/*jslint unparam:true */
/*jshint unused:false */
if (value === Undefined) {
value = String(value);
}
return value;
});
}());

it's an old question, but if anyone still looking for a solution can try this
function restructureObject(object){
let result = {};
for(let key in object){
const splittedKeys = key.split('.');
if(splittedKeys.length === 1){
result[key] = object[key];
}
else if(splittedKeys.length > 2){
result = {...result, ...{[splittedKeys.splice(0,1)]: {}} ,...restructureObject({[splittedKeys.join('.')]: object[key]})}
}else{
result[splittedKeys[0]] = {[splittedKeys[1]]: object[key]}
}
}
return result
}

Find key contain dot and replace with #

I have nested object which can have any number of key at any depth.
I want to replace "." in all keys(if contain) with "#" How we can do this in efficient way.
Example Node js object
obj:{
"BotBuilder.Data.SessionState": {
"lastAccess": 1492886892545,
"version": 14,
"callstack": [
{
"id": "*:/",
"state": {
"BotBuilder.Data.WaterfallStep": 0,
"BotBuilder.Data.Intent": "welcomeDialog"
}
}
]
}
Currently i am using hard coded solution , but any keys can be possible in object at any level which contain "." I want generalize way to solve this problem
My code :
replaceDot:function(doc){
var finalobj={}
var finaldata={}
var finalcallstack=new Array();
console.log("doc==>",doc)
var callstack=doc["data"]["BotBuilder.Data.SessionState"]["callstack"]
for(var i = 0; i < callstack.length; i++) {
var tempcallstack={}
if("BotBuilder.Data.WaterfallStep" in callstack[i]["state"]){
tempcallstack["id"]=callstack[i]["id"]
var tempstate={}
tempstate["state"]=callstack[i]["state"]
tempstate["state"]["BotBuilder#Data#WaterfallStep"]=tempstate["state"]["BotBuilder.Data.WaterfallStep"]
tempstate["state"]["BotBuilder#Data#Intent"]=tempstate["state"]["BotBuilder.Data.Intent"]
delete tempstate["state"]["BotBuilder.Data.WaterfallStep"]
delete tempstate["state"]["BotBuilder.Data.Intent"]
tempcallstack["state"]=tempstate["state"];
finalcallstack.push(tempcallstack);
}
else{
finalcallstack.push(callstack[i]);
}
}
var obj={}
finalobj["lastAccess"]=doc["data"]["BotBuilder.Data.SessionState"]["lastAccess"]
finalobj["version"]=doc["data"]["BotBuilder.Data.SessionState"]["version"]
finalobj["callstack"]=finalcallstack;
obj["BotBuilder#Data#SessionState"]=finalobj
var secondrootobj={"BotBuilder#Data#SessionState":finalobj}
return secondrootobj;
}

Here's a function that takes an object or array, and target and replacement values for the keys of that object. It will then return a new object where instances of target are replaced with replacement (using String.prototype.replace) in the resulting object's keys.
var substituteKeyDeep = function(obj, target, replacement) {
// Get the type of the object. Array for arrays, Object for objects, null for anything else.
try {
var type = obj.constructor === Array ? Array
: (obj.constructor === Object ? Object : null);
} catch (err) {
// A try/catch is actually necessary here. This is because trying to access the `constructor` property
// of some values throws an error. For example `null.constructor` throws a TypeError.
var type = null;
}
if (type === Array) {
// Simply do a recursive call on all values in array
var ret = [];
for (var i = 0, len = obj.length; i < len; i++) {
ret[i] = substituteKeyDeep(obj[i], target, replacement);
}
} else if (type === Object) {
// Do a recursive call on all values in object, AND substitute key values using `String.prototype.replace`
var ret = {};
for (var k in obj) {
ret[k.replace(target, replacement)] = substituteKeyDeep(obj[k], target, replacement);
}
} else {
// For values that aren't objects or arrays, simply return the value
var ret = obj;
}
return ret;
};
var data = {
"BotBuilder.Data.SessionState": {
"lastAccess": 1492886892545,
"version": 14,
"callstack": [
{
"id": "*:/",
"state": {
"BotBuilder.Data.WaterfallStep": 0,
"BotBuilder.Data.Intent": "welcomeDialog"
}
}
]
}
};
var dataWithRenamedKeys = substituteKeyDeep(data, /\./g, '#');
console.log(dataWithRenamedKeys);
Note that in the example, the replacement value (/\./g) is a regex expression, not a string. This is because a regex expression with the global modifier (g) is required to replace ALL instances of the occurrence, not just the first, in the object's keys.
EDIT: Quick disclaimer! This solution will exceed the stack if substituteKeyDeep is called with an object that has circular references.

How to store a javascript function in JSON

I have a JS object I would like to save in Local Storage for future use, and I cannot parse it to a string.
Code:
JSON.stringify({
a: 5,
b: function (param) {
return param;
}
})
Result:
"{"a":5}"
How do I save it for future use, if not with JSON?
(And creating my own Lexer-Parser to interupt string function I dont think is an option)

I'd recommend this approach:
Store arguments and the body in your json:
{"function":{"arguments":"a,b,c","body":"return a*b+c;"}}
Now parse json and instantiate the function:
var f = new Function(function.arguments, function.body);
I think it's save

Usually a question like this indicates an X/Y problem: You need to do X, you think Y will help you do that, so you try to do Y, can't, and ask how to do Y. It would frequently be more useful to ask how to do X instead.
But answering the question asked: You could use replacer and reviver functions to convert the function to a string (during stringify) and back into a function (during parse) to store a string version of the function, but there are all sorts of issues with doing that, not least that the scope in which the function is defined may well matter to the function. (It doesn't matter to the function you've shown in the question, but I assume that's not really representative.) And converting a string from local storage into code you may run means that you are trusting that the local storage content hasn't been corrupted in a malicious way. Granted it's not likely unless the page is already vulnerable to XSS attacks, but it's an issue to keep in mind.
Here's an example, but I don't recommend it unless other options have been exhausted, not least because it uses eval, which (like its close cousin new Function)) can be a vector for malicious code:
// The object
var obj = {
a: 5,
b: function (param) {
return param;
}
};
// Convert to JSON using a replacer function to output
// the string version of a function with /Function(
// in front and )/ at the end.
var json = JSON.stringify(obj, function(key, value) {
if (typeof value === "function") {
return "/Function(" + value.toString() + ")/";
}
return value;
});
// Convert to an object using a reviver function that
// recognizes the /Function(...)/ value and converts it
// into a function via -shudder- `eval`.
var obj2 = JSON.parse(json, function(key, value) {
if (typeof value === "string" &&
value.startsWith("/Function(") &&
value.endsWith(")/")) {
value = value.substring(10, value.length - 2);
return (0, eval)("(" + value + ")");
}
return value;
});
document.body.innerHTML = obj2.b(42);
The construct (0, eval)("(" + value + ")"); ensures that eval runs at global scope rather than within the scope of the reviver function. Normally eval has a magic ability to use the scope you call it in, but that only works when you call it directly. Indirect eval as shown (or just var e = eval; e("(" + value + ")");) doesn't have that magic ability, it runs at global scope.

You can't store functions in JSON.
The value in JSON may contain only string, number, object, array, true, false or null:
Check out it on JSON site.

One simple way of doing this is
var dstr = JSON.stringify( { a: 5
, b: x => x
}
, (k,v) => typeof v === "function" ? "" + v : v
);

I've taken to storing the function name, along with the parameter values, in an array, with the first item in the array being the function name prepended with a $, to separate them from normal arrays.
{
"object": {
"your-function": ["$functionName", "param-1", "param-2"],
"color": ["$getColor", "brand", "brand-2"],
"normal-array": ["normal", "array"]
...
}
}
In the above example I have Sass and JS functions to retrieve color values from a global map/object. Parsing the function in this manner naturally requires custom code, but in terms of "storing" functions in JSON, I like this way of doing it.

I have created JSON.parseIt() and JSON.stringifyIt() functions based on the first answer without using eval
JSON.stringifyIt = (obj)=>{
return(
JSON.stringify(obj, function(key, value) {
if (typeof value === "function") {
return "/Function(" + value.toString() + ")/";
}
if(typeof value === "string"){
return "/String(" + value.toString() + ")/"
}
return value;
})
)
}
JSON.parseIt=(json)=>{
return(
JSON.parse(json, function(key, value) {
if (typeof value === "string" &&
value.startsWith("/Function(") &&
value.endsWith(")/")) {
value = value.substring(10, value.length - 2);
var string = value.slice(value.indexOf("(") + 1, value.indexOf(")"));
if(/\S+/g.test(string)){
return (new Function(string,value.slice(value.indexOf("{") + 1, value.lastIndexOf("}"))))
}else{
return (new Function(value.slice(value.indexOf("{") + 1, value.lastIndexOf("}"))));
}
}
if (typeof value === "string" &&
value.startsWith("/String(") &&
value.endsWith(")/")){
value = value.substring(8, value.length - 2);
}
return value;
})
)
}
// DEMO
var obj = {
string:"a string",
number:10,
func:()=>{
console.log("this is a string from a parsed json function");
},
secFunc:(none,ntwo)=>{console.log(none + ntwo)} ,
confuse:"/Function(hello)/"
}
const stringifiedObj = JSON.stringifyIt(obj);
console.log("the stringified object is: ",stringifiedObj);
const parsedObj = JSON.parseIt(stringifiedObj);
// console.log("the parsed object is: ",parsedObj);
console.log(parsedObj.string);
console.log(parsedObj.number);
console.log(parsedObj.confuse);
parsedObj.func();
parsedObj.secFunc(5,6);
The problems I fixed were
Removed eval.
there was a problem in the stringifying and parsing that if I give a string like
"/Function(hello)/" will be a function when parsed
Made it to two functions
Added parameter insertation

For someone that still need include, for whatever reason, the function definition in JSON, this code can help (but can be slow depending object size):
function Object2JsonWithFunctions(o, space = null) {
var functionList = {}
var fnSeq = 0;
var snrepl = function(k,v){
if(typeof v === 'function'){
fnSeq++;
var funcName = `___fun${fnSeq}___`;
var funcText = ''+v;
functionList[funcName] = funcText
return funcName;
}
return v;
}
var RawJson = JSON.stringify(o, snrepl, space);
for(func in functionList){
var PropValue = `"${func}"`;
RawJson = RawJson.replace(PropValue, functionList[func])
}
return RawJson;}
The code will do the normal convert to JSON.
For functions, the original stringify will return as "prop":"function()..." (function as a string)... The code above will create a placeholder (e.g: "prop":"fn1") and create a function list... After, will replace every placeholder to original function body...

How do I write a recursive function in Javascript to add up all of the string values of a deeply nested object?

Say I have this object:
{
"prop1":"Hello",
"prop2":{
"prop1":{
"prop1":"Tablecloth",
"prop2":"Indians"
},
"prop2":"JuicyJuice"
},
"prop3":"Sponge",
"prop4":{"Bob":"Squarepants"}
}
I would like a recursive function that will return HelloTableclothIndiansJuicyJuiceSpongeSquarepants.
Whatever object I put it, I want it to cycle though until it gets all of the strings and adds them all up.
Thank you!

Here's a very simple implementation that should work for simple objects like this:
var walkProps = function(obj) {
var s = "";
for(var x in obj)
{
if(typeof obj[x] === "string")
s += obj[x];
else
s += walkProps(obj[x]);
}
return s;
}
Demonstration
Note, though, that that depends on the order in which for-in visits the properties on the object, which is not specified and can vary by engine and by how the object is constructed (for instance, the order in which the properties were added).
Update: With some slight modification, this can be used to return the values based on the alphabetical order of the keys. This method is not sensitive to implementation-dependent ordering of properties:
var walkProps = function(obj) {
var s = "", i = 0, keys = Object.keys(obj).sort(), i;
for(; i < keys.length; i++)
{
if(typeof obj[keys[i]] === "string")
s += obj[keys[i]];
else
s += walkProps(obj[keys[i]]);
}
return s;
}
So even if "prop3" comes before "prop2" it will still return the same output.
Demonstration

You would need to write a function that loops over an object's properties and see if they are a string, and then append the strings to an output. If the property is an object rather than a string, you would want to call the function on this object and append it's return value to your total output.
You can loop over an object's properties using for...in like:
var MyObject = {
'a': 'string1',
'b': 'string2'
};
for (var key in MyObject) {
var value = MyObject[key];
}
To check if a property is a string you would want to do:
typeof value === "string"
Which will return true/false accordingly.

As mentioned, for( var b in a ) may not preserve ordering:
// Return array of string values
function getStrings(a) {
if( typeof(a) == "string" ) return [a];
var list = [];
for( var b in a ) list = list.concat(getStrings(a[b]));
return list;
}
Applied to OP's data:
var a = {
"prop1":"Hello",
"prop2":{
"prop1":{
"prop1":"Tablecloth",
"prop2":"Indians"
},
"prop2":"JuicyJuice"
},
"prop3":"Sponge",
"prop4":{"Bob":"Squarepants"}
}
getStrings(a).join(); // "Hello,Tablecloth,Indians,JuicyJuice,Sponge,Squarepants"
// Or as asked for by OP (again, order is not guaranteed)
getStrings(a).join(''); // "HelloTableclothIndiansJuicyJuiceSpongeSquarepants"

Develop Reference

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