I know that I can create an associative array like this:
var MyAssocArray = {'sky':'blue', 'grass':'green'};
And I am very fond of using this method.
What I would like to do and am having trouble with is this:
I have strings saved like this:
var MyString = "'sky':'blue', 'grass':'green'";
And I want to be able to do this now:
var MyAssocArray = {MyString};
When I try that - I get this error:
invalid object initializer
What am I doing wrong?
How can I achieve this?
I found a different solution using PHP and JavaScript. The associative array string is echoed in the JavaScript code:
var Multidimensional_Arr[Multidimensional_Array_Key_Name] = {<?php echo $String_Pulled_From_Database; ?>}; // i.e. 'sky':'blue', 'grass':'green'
// The same can be done for a one-dimensional array
var My_Single_Dime_Arr = {<?php echo $String_Pulled_From_Database; ?>}; // i.e. 'sky':'blue', 'grass':'green'
Use JSON -- it's serialized JavaScript Object Notation and is pretty close to what you're doing.
You'd need to do
var MyAssocArray = JSON.parse(MyString);
Also, JSON uses double quotes, not single quotes; if you use simple objects, you can probably write code to just replace ' with "" in your strings, but it's tricky if the strings contain double-quotes.
If you are using a browser that doesn't implement JSON.parse(), you can either use the implementation on the JSON website (see links at bottom of this page) or if you're using jQuery, there's jQuery.parseJSON().
Warning: Your solution has a security risk, unless you are sure the data in the database has been sanitized:
var My_Single_Dime_Arr = {<?php echo $String_Pulled_From_Database; ?>}
This is equivalent to a call to eval(); if your database string has any malicious code it can do bad things. This is one reason why JSON was invented -- it's easy to ensure that its contents are valid (and hence safe) before evaluated.
Your overall architecture, as you have presented it to us, is [data in database] -> server-side PHP -> client-side JavaScript. This is a classic example of serialized data. I realize you may have constraints to keep your system running without interruption, but a strict serialization format would make your system more secure.
If you are sure the data is safe, then you could do:
var MyAssocArray = eval('{' + MyString + '}');
You can't do that.
To achieve what you want, use the split() function to split your string into comma-separated tokens first. Then each token should further be split by the ':' character.
Then push the two tokens obtained by the last split as the key and the value of your associative array.
Related
var jsonString = '{"DeviceId":3,"results":{"1":"[{\"x\":513,\"y\":565,\"width\":175,\"hight\":208}]"}}';
var message = JSON.parse(jsonString);
I got an error saying Unexpected token u in JSON at position 0
at JSON.parse.
Could you please guide me what's wrong?
THanks in advance!
At the last few characters looks wrong. The :212 has no sense as the value (that long array) for key "1" was already set, so that later :212 looks weird
Also enclosing it in single quotes it makes that all be like a huge string, and not as an array structure.
See Results key as value contains a sub array which contain "1" key which as value contains a string enclosing another json array (but escaped as plain string, so no structurally accesible for the main object . But that string if post -processed the :212 is paired to what? , no key, no comma neighter , to the precedent whole array which already was the value, not the key?. Anyway weird.
In your JSON string, there is wrong something with ":212", as it's not valid JSON, because it doesn't have any property that it's mapping the value for. For example, you are mapping values for width and height with properties keys. But for "212", there is no property.
Here is the above JSON formatted:
var jsonString = '{"DeviceId":"3","results":{"1":"[{\\"x\\":513,\\"y\\":565,\\"width\\":175,\\"hight\\":208}]"}}'
var message = JSON.parse(jsonString);
If you want to format the results, you can do to it, there is no error on it:
JSON.parse(message.results['1'])
Here is the JS Bin link for above code: https://jsbin.com/fiyeyet/edit?js,console
Just an advice
Professional code is all about proper spacing, proper identation , proper commenting, don't try to write down all within one single line, structure it VISUALLY nice to see nice to read nice to comprehend, and you will be approved in most jobs.
Hint: declare a normal array/object , convert it to json string using the proper function, then use the string variable returned by the function to test your code or whatever doing. That way, you can write down in the source really nice the structure.
I am experiencing an issue where I am in need of passing a JSON as an HTML attribute. I have the JSON string:
{"filename":"myFile.js","content":"var k = 'My Value'"}
Which I am passing to a html attribute:
<ide file-json='{"filename":"myFile.js","content":"var k = 'My Value'"}'></ide>
The issue occurs where var k = 'My Value' as the ' mark is unescaped and causing the html parser to think the value of attribute file-json is {"filename":"myFile.js","content":"var k = rather than the full string. The file-json attribute is going to be read via javascript for additional processing.
The values for both the json keys of filename and content are user generated, and can have almost any value. Is there a way escape the entire file-json attribute?
Things that I have already tried, and the reason for their failure are below: (The actual json input can be extremely large.)
Use a giant regular expression to escape any offending instances in the json file. This for two primary reasons, the first being that it was slow, but more importantly it is a "dumb" solution and often makes mistakes causing additional errors, and data corruption.
Convert the entire json structure into base64/hex; pass this encoded structure to file-json; and then in the javascript when it is read, convert it from base64 back into a json string; and finally continue processing. This so far is the best solution that I have come up with as it is the only one that cannot cause data corruption. However it is both slow and consists of a large number of moving parts leading to issues in maintainability and expandability.
Your json looks like valid json, so a simple JSON.stringify should do the job
var json = {"filename":"myFile.js","content":"var k = 'My Value'"}
var stringified = JSON.stringify(json);
// or whatever element identifier you have
document.getElementById('foo').setAttribute('file-json', stringified)
if not and its really a string, simply add JSON.parse()
var stringified = JSON.stringify(JSON.parse(json));
FIDDLE
I want to edit JavaScript in a textarea and store it back into a JavaScript object. For example I have this object:
var item1 = {
'id' : 1,
'title':'title',
'sourcecode' : "alert('hallo')"
};
If I would change the content to alert("hallo") or a even more complex example does this break my object?
I would think there is some escape function like this https://developer.mozilla.org/de/docs/Web/JavaScript/Reference/Global_Objects/escape. But it is marked as deprecated.
So if this is deprecated what would be the right way for storing complex JavaScript code into a JavaScript object?
Should I use stringify ?
https://developer.mozilla.org/de/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify
The JSON.stringify() method converts a JavaScript value to a JSON
string, optionally replacing values if a replacer function is
specified, or optionally including only the specified properties if a
replacer array is specified.
This does not read like there is an automated escape build in.
If you need to send the data to a server, I'd say you should encodeURI your sourceCode, and then JSON.stringify the entire object. When retreiving data from the server, you should decodeURI the sourceCode
I have code
data = "{isShowLoginPopup:true,newFavOfferId:1486882}";
I want to convert it into JS object (not in JSON) and use it in this way:
data.newFavOfferId = ...
How can I do this?
If your source is trusted, the simplest solution is to use eval :
data = eval('('+data+')');
If you don't trust the source, then you'd better specify what you can have and parse the string manually (not terribly hard if you have only one level of properties for example).
Another solution (depending on your real data) would be to change your data into JSON by inserting the missing quotes :
data = JSON.parse(datareplace(/({|,)\s*([^:,}{]+)\s*(:)/g,'$1"$2"$3'));
just remove the quotes
data = {
isShowLoginPopup:true,
newFavOfferId:1486882
};
Fiddle: http://jsfiddle.net/QpZ4j/
just remove quotes "" from the
data = "{isShowLoginPopup:true,newFavOfferId:1486882}";
DEMO
Whilst on the surface this looks like JSON data, it's malformed and therefore it does not work directly with JSON.parse(). This is because JSON objects require keys to be wrapped in quotes...
therefore:
"{isShowLoginPopup:true,newFavOfferId:1486882}"
as valid JSON should be:
"{\"isShowLoginPopup\":true,\"newFavOfferId\":1486882}"
So what you have there in fact IS a JavaScript object, not JSON, however the problem you have is that this is a JavaScript object as a string literal. If this is hard coded, then you need to just remove the " from the beginning and end of the string.
var data = {isShowLoginPopup:true,newFavOfferId:1486882};
If this object is serialized and requires transmission from/to a server etc, then realistically, it needs to be transmitted as a JSON formatted string, which can then be de-serialized back into a JavaScript object.
var data = JSON.parse("{\"isShowLoginPopup\":true,\"newFavOfferId\":1486882}");
This is for a gaming application.
In my game I want to save special effects on a player in a single field of my database. I know I could just put a refrence Id and do another table and I haven't taken that option off the table.
Edit: (added information) This is for my server in node not the browser.
The way I was thinking about storing the data is as a javascript object as follows:
effects={
shieldSpell:0,
breatheWater:0,
featherFall:0,
nightVision:0,
poisonResistance:0,
stunResistance:0,
deathResistance:0,
fearResistance:0,
blindResistance:0,
lightningResistance:0,
fireResistance:0,
iceResistance:0,
windResistance:0}
It seems easy to store it as a string and use it using effects=eval(effectsString)
Is there an easy way to make it a string or do I have to do it like:
effectsString=..."nightVision:"+effects.nightVision.toString+",poisonResistance:"+...
Serialize like that:
JSON.stringify(effects);
Deserialize like that:
JSON.parse(effects);
Use JSON.stringify
That converts a JS object into JSON. You can then easily deserialize it with JSON.parse. Do not use the eval method since that is inviting cross-site scripting
//Make a JSON string out of a JS object
var serializedEffects = JSON.stringify(effects);
//Make a JS object from a JSON string
var deserialized = JSON.parse(serializedEffects);
JSON parse and stringify is what I use for this type of storatge
var storeValue = JSON.stringify(effects); //stringify your value for storage
// "{"shieldSpell":0,"breatheWater":0,"featherFall":0,"nightVision":0,"poisonResistance":0,"stunResistance":0,"deathResistance":0,"fearResistance":0,"blindResistance":0,"lightningResistance":0,"fireResistance":0,"iceResistance":0,"windResistance":0}"
var effects = JSON.parse(storeValue); //parse back from your string
Here was what I've come up with so far just wonering what the downside of this solution is.
effectsString="effects={"
for (i in effects){
effectsString=effectsString+i+":"+effects[i]+","
}
effectsString=effectsString.slice(0,effectsString.length-1);
effectsString=effectsString+"}"
Then to make the object just
eval(effectsString)