Using Visual Studio 2012, on a Razor view page, in the JavaScript section, I am getting what I think is a battle between Razor syntax vs JavaScript syntax. In particular, the trailing semicolon in the script section is flagged by intellisense and a compiler warning (not error) is delivered:
'Warning 13 Syntax error'.
If I remove it, then I get a statement termination recommendation (ReSharper in this case, but just good practice).
<script type="text/javascript">
$().ready(function(){
var customer = #Html.Raw(ViewBag.CustomerJSON); // <- Razor (I think) doesn't like this semicolon
});
</script>
Is this a bug in Razor? If so, is there a way I can rewrite this to avoid this issue?
Is this a bug in Razor?
Absolutely not. Run your application, and it will work as expected.
It is a bug in the tools you are using (Visual Studio 2012, ReSharper, ...) that are incapable of recognizing perfectly valid syntax and warning you about something that you shouldn't be warned about. You could try opening an issue on the Microsoft Connect site and signalling this bug if that hasn't already been done.
Since this still seems to be happening and it is a nuisance I figured I will at least let others know what I ended up using as a "hack". I don't want to ignore the warning and would rather accept a hokier syntax (and yes someone is going to say this will kill performance :))
What I use as a workaround is to use a client side addition at the end. For me this error occurred on defining an "integer" constant, so
window.foo = #(Model.Something);
gave me the good old semicolon error. I simply changed this to:
window.foo = #Model.Something + 0;
(In the stated questions case you should just be able to add '', so + ''.
I know there is a whole another addition happening on the client and it isn't elegant, but it does avoid the error. So use it or don't, but I prefer this over seeing the warning/error.
If someone knows of a server-side syntactical workaround for this I would prefer this to the client-side one, so please add.
I found that wrapping the Razor syntax in a JavaScript identity function also makes the IDE happy.
<script type="text/javascript">
#* I stands for Identity *#
function I(obj) { return obj; }
$().ready(function(){
var customer = I(#Html.Raw(ViewBag.CustomerJSON));
});
</script>
This worked for me:
var customer = #Html.Raw(ViewBag.CustomerJSON + ";")
Here's a workaround for booleans:
var myBool = #(Model.MyBool ? "true;" : "false;")
This worked for me
#Html.Raw(string.Format("var customer = {0};", ViewBag.CustomerJSON));
<script type="text/javascript">
$().ready(function(){
var customerName = ('#ViewBag.CustomerName'); // <- wrap in parens
});
</script>
Isn't it as simple as wrapping in parentheses? Putting values through the console seem to work fine with no side effect.
It works for strings, but it still gives the error for non-quoted values, but I still like this for string values. For numbers you could just use parseInt('#Model.TotalResultCount', 10).
Related
Here's a new one, IE11 is throwing errors on code that works in every other browser.
Anyway, after a few hours of "fixing" code so that IE11 doesn't fall on its own face I have come across an error I just cannot seem to find a solution to. Here is the code in question:
$('input[name="messageAccount"]').change(function () {
$aButton.show();
var addedIds = $("#hdnfield").val();
if (addedIds == null || addedIds === "") {
$("#hdnfield").val(this.value);
} else {
$("#hdnfield").val(`${addedIds}${this.value}`);
};
});
This is nested on the inside of the success call in an Ajax request. IE's debugger is saying the error is coming from the content of the else statement but it's also reading all the brackets wrong. For example the opening parenthesis on this function is being "closed" after the closing bracket for the Ajax request... (hopefully that made sense).
Has anyone else had a similar issue with IE before? I've got a number of other bugs to fix so if there are any replies I will post back as soon as I can. Thanks in advance.
EDIT: just for reference I am currently running this locally and is part of what will become an internally hosted web app.
It's because "`" (template strings) is not supported by IE : http://caniuse.com/#search=string
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Template_literals
See https://stackoverflow.com/a/27678299/2195875
To avoid this error you can either use a ES6 to ES5 transpiler, or just directly write valid ES5 javascript:
instead of
`string text ${expression} string text`
write
"string text "+expression+" string text"
You can also add polyfill to your html:
<script src="https://cdnjs.cloudflare.com/ajax/libs/babel-polyfill/6.26.0/polyfill.min.js"/>
Certain dynamic web frameworks use this code fragment
<script>
appSettings = JSON.parse(
decodeURIComponent(
"%7B%22setting1%22%3A%22foo%22%2C%22setting2%22%3A123%7D"));
</script>
Is there a standard HTML5/JavaScript problem are they trying to solve with this code. Why not just
<script>
appSettings = {"setting1":"foo","setting2":123};
</script>
Note: this is dynamically generated code. I'm assuming on the server they are doing something like
var settingsString = encodeURIComponent(JSON.stringify(settings));
var output = '<script>appSettings=JSON.parse(decodeURIComponent("' +
settingsString +
'"));</script>';
But it seems like it would work just as well like this
var settingsString = JSON.stringify(settings);
var output = '<script>appSettings=' +
settingsString +
';</script>';
One idea is the latter could contain code but they are the ones providing the string, it's not user data so they're no chance it could be code. Plus using JSON.stringify on the server would remove all code. On the client even then a simple JSON.parse of a JSON.stringifyied object would prevent code.
Is there a concrete problem being solved by the triple parsing? Once by JavaScript, once by decodeURIComponent, once by JSON.parse?
THIS IS NOT AN OPINION BASED QUESTION
The question is what problem is being solved. Either there is a problem being solved or there is not. No opinions required to answer that question. For example if JSON.stringify happens to emit unparseable code sometimes (which as far I know it doesn't but if someone knows better then that would be a good answer as to why).
Also note: I'm not asking why their framework does this. I'm asking if there is real problem being solved in standard HTML5/JavaScript. In other words, should I adopt this pattern because I'm going to run into an issue someday if I don't.
Is there a concrete problem being solved by the triple parsing?
Yes. Your suggested solution has two problems:
It's parsed as HTML. Things like </script> can cause havoc in an inline script.
It's parsed as JS. Not all JSON strings are valid JS literals.
The decodeURIComponent + JSON.parse approach is a crude workaround however and looks more like a quick fix than a proper solution.
#katspaugh is correct
Testing
var settingString = JSON.stringify({
"</script>": "<script>bar=123</script>",
});
Generates the code for the above example as
<script>
appSettings = {"</script>":"<script>window.bar=123</script>"}
</script>
Which fails to parse as HTML. Adding the encodeURIComponent on the server JSON.parse(decodeURIComponent(...)) on the client fixes that issue
DO NOT USE IT.
let str = `C:\\Users\\Administrator\\Desktop\\小灶\\GT4T_translated_Chinese Simplified (简体中文)\\2013\%2F193461.pdf`
let newStr = decodeURIComponent(JSON.parse(`"${str}"`))
Depending on the str content, you may get unexpected errors. The code above will cause this error:
SyntaxError: Unexpected token U in JSON at position 4
I have some big set of different javascript-snippets (several thousands), and some of them have some stupid errors in syntax (like unmatching braces/quotes, HTML inside javascript, typos in variable names).
I need a simple way to check JS syntax. I've tried JSLint but it send too many warnings about style, way of variable definitions, etc. (even if i turn off all flags). I don't need to find out style problems, or improve javascript quality, i just need to find obvious syntax errors. Of course i can simply check it in browser/browser console, but i need to do it automatically as the number of that snippets is big.
Add:
JSLint/JSHint reports a lot of problems in the lines that are not 'beauty' but working (i.e. have some potential problems), and can't see the real problems, where the normal compiler will simply report syntax error and stop execution. For example, try to JSLint that code, which has syntax errors on line 4 (unmatched quotes), line 6 (comma required), and line 9 (unexpected <script>).
document.write('something');
a = 0;
if (window.location == 'http://google.com') a = 1;
document.write("aaa='andh"+a+"eded"');
a = {
something: ['a']
something2: ['a']
};
<script>
a = 1;
You could try JSHint, which is less verbose.
Just in case anyone is still looking you could try Esprima,
It only checks syntax, nothing else.
I've found that SpiderMonkey has ability to compile script without executing it, and if compilation failed - it prints error.
So i just created small wrapper for SpiderMonkey
sub checkjs {
my $js = shift;
my ( $js_fh, $js_tmpfile ) = File::Temp::tempfile( 'XXXXXXXXXXXX', EXLOCK => 0, UNLINK => 1, TMPDIR => 1 );
$| = 1;
print $js_fh $js;
close $js_fh;
return qx(js -C -f $js_tmpfile 2>&1);
}
And javascriptlint.com also deals very good in my case. (Thanks to #rajeshkakawat).
Lots of options if you have an exhaustive list of the JSLint errors you do want to capture.
JSLint's code is actually quite good and fairly easy to understand (I'm assuming you already know JavaScript fairly well from your question). You could hack it to only check what you want and to continue no matter how many errors it finds.
You could also write something quickly in Node.js to use JSLint as-is to check every file/snippet quickly and output only those errors you care about.
Just use node --check filename
Semantic Designs' (my company) JavaScript formatter read JS files and formats them. You don't want the formatting part.
To read the files it will format, it uses a full JavaScript parser, which does a complete syntax check (even inside regular expressions). If you run it and simply ignore the formatted result, you get a syntax checker.
You can give it big list of files and it will format all of them. You could use this to batch-check your large set. (If there are any syntax errors, it returns a nonzero error status to a shell).
I'd like to start by saying that my code is working perfectly, this is more a "how best to do it" kind of question.
So I have code like this in my .aspx file:
function EditRelationship() {
var projects=<%= GetProjectsForEditRelationship() %>;
// fill in the projects list
$('#erProjectsSelect').empty();
for(var i in projects)
$('#erProjectsSelect').append('<option value='+projects[i][0]+'>'+projects[i][1]+'</option>');
var rels=<%= GetRelationshipsForEditRelationship() %>;
// etc
}
Again, it's working fine. The problem is that VS2008 kinda chokes on code like this, it's underlining the < character in the tags (with associated warnings), then refusing to provide code completion for the rest of the javascript. It's also refusing to format my document anymore, giving parsing errors. The last part is my worst annoyance.
I could put some of these in evals I guess, but it seems sorta dumb to add additional layers and runtime performance hits just to shut VS up, and it's not always an option (I can't remember off the top of my head where this wasn't an option but trust me I had a weird construct).
So my question is, how do you best write this (where best means fewest VS complaints)? Neither eval nor ajax calls fit this imo.
If your aim is to reduce VS complaints, and if you are running asp.net 4 (supporting Static client Ids), maybe a strategy like the following would be better?
Create a ASP:HiddenField control, set its ClientIdMode to "Static"
Assign the value of GetRelationshipsForEditRelationship() to this field on page load
In your javascript, read the value from the hidden field instead, I assume you know how to do this.
It's more work than your solution, and you will add some data to the postback (if you perform any) but it won't cause any VS complaints I guess :)
You could do this from your page in the code-behind
ClientScript.RegisterArrayDeclaration("projects", "1, 2, 3, 4");
or to construct something like JSON you could write it out
ClientScript.RegisterClientScriptBlock(GetType(), "JSONDeclarations", "your json stuff");
UPDATE Based on my comment
<script id="declaration" type="text/javascript">
var projects=<%= GetProjectsForEditRelationship() %>;
var rels=<%= GetRelationshipsForEditRelationship() %>;
</script>
<script type="text/javascript">
function EditRelationship() {
// fill in the projects list
$('#erProjectsSelect').empty();
for(var i in projects)
$('#erProjectsSelect').append('<option value='+projects[i][0]+'>'+projects[i][1]+'</option>');
}
</script>
I don't have VS2008 installed to test with, so take this with a grain of salt, but have you tried something like this?
var projects = (<%= GetProjectsForEditRelationship() %>);
Something like that might trick the JavaScript parser into ignoring the content of your expression.
For what it's worth, VS2010 correctly parses and highlights your original code snippet.
Is it an option to move this to VS2010? I just copied and pasted your code and the IDE interpreted it correctly.
The best solution is to put javascript in a separate file and avoid this entirely. For this particular function, you're doing server-side work. Why not build the list of options that you intend to add dynamically in codebehind, put them in a hidden div, and then just have jQuery add them from the already-rendered HTML?
If you have a situation where you really want to dynamically create a lot javascript this way, consider using ScriptManager in codebehind to set up the variables you'll need as scripts and register them, then your inline script won't need to escape
ScriptManager.RegisterClientScript("projects = " + GetProductsForEditRelationship());
(Basically, that is not the complete syntax, which is context dependent). Then refer to "projects" in your function.
(edit)
A little cleaner way to do this on a larger scale, set up everything you need like this in codebehind:
string script = "var servervars = {" +
"GetProductsForEditRelationship: " + GetProductsForEditRelationship() +
"GetRelationshipsForEditRelationship: " + GetRelationshipsForEditRelationship() +
"}"
and refer to everything like:
servervars.GetProductsForEditRelationship
If you do this a lot, of course, you can create a class to automate the construction of the script.
Some users are reporting occasional JS errors on my site. The error message says "Expected identifier, string or number" and the line number is 423725915, which is just an arbitrary number and changes for each report when this occurs.
This mostly happens with IE7/ Mozilla 4.0 browsers.
I scanned my code a bunch of times and ran jslint but it didn't pick anything up - anyone know of the general type of JS problems that lead to this error message?
The cause of this type of error can often be a misplaced comma in an object or array definition:
var obj = {
id: 23,
name: "test", <--
}
If it appears at a random line, maybe it's part of an object defintion you are creating dynamically.
Using the word class as a key in a Javascript dictionary can also trigger the dreaded "Expected identifier, string or number" error because class is a reserved keyword in Internet Explorer.
BAD
{ class : 'overlay'} // ERROR: Expected identifier, string or number
GOOD
{'class': 'overlay'}
When using a reserved keyword as a key in a Javascript dictionary, enclose the key in quotes.
Hope this hint saves you a day of debugging hell.
Actually I got something like that on IE recently and it was related to JavaScript syntax "errors". I say error in quotes because it was fine everywhere but on IE. This was under IE6. The problem was related to JSON object creation and an extra comma, such as
{ one:1, two:2, three:3, }
IE6 really doesn't like that comma after 3. You might look for something like that, touchy little syntax formality issues.
Yeah, I thought the multi-million line number in my 25 line JavaScript was interesting too.
Good luck.
This is a definitive un-answer: eliminating a tempting-but-wrong answer to help others navigate toward correct answers.
It might seem like debugging would highlight the problem. However, the only browser the problem occurs in is IE, and in IE you can only debug code that was part of the original document. For dynamically added code, the debugger just shows the body element as the current instruction, and IE claims the error happened on a huge line number.
Here's a sample web page that will demonstrate this problem in IE:
<html>
<head>
<title>javascript debug test</title>
</head>
<body onload="attachScript();">
<script type="text/javascript">
function attachScript() {
var s = document.createElement("script");
s.setAttribute("type", "text/javascript");
document.body.appendChild(s);
s.text = "var a = document.getElementById('nonexistent'); alert(a.tagName);"
}
</script>
</body>
This yielded for me the following error:
Line: 54654408
Error: Object required
Just saw the bug in one of my applications, as a catch-all, remember to enclose the name of all javascript properties that are the same as keyword.
Found this bug after attending to a bug where an object such as:
var x = { class: 'myClass', function: 'myFunction'};
generated the error (class and function are keywords)
this was fixed by adding quotes
var x = { 'class': 'myClass', 'function': 'myFunction'};
I hope to save you some time
http://closure-compiler.appspot.com/home will pick this error up with an accurate reference to the actual line number in the offending script.
As noted previously, having an extra comma threw an error.
Also in IE 7.0, not having a semicolon at the end of a line caused an error. It works fine in Safari and Chrome (with no errors in console).
IE7 is much less forgiving than newer browsers, especially Chrome. I like to use JSLint to find these bugs. It will find these improperly placed commas, among other things. You will probably want to activate the option to ignore improper whitespace.
In addition to improperly placed commas, at this blog in the comments someone reported:
I've been hunting down an error that only said "Expected identifier"
only in IE (7). My research led me to this page. After some
frustration, it turned out that the problem that I used a reserved
word as a function name ("switch"). THe error wasn't clear and it
pointed to the wrong line number.
Remove the unwanted , sign in the function. you will get the solution.
Refer this
http://blog.favrik.com/2007/11/29/ie7-error-expected-identifier-string-or-number/
This error occurs when we add or missed to remove a comma at the end of array or in function code. It is necessary to observe the entire code of a web page for such error.
I got it in a Facebook app code while I was coding for a Facebook API.
<div id='fb-root'>
<script type='text/javascript' src='http://connect.facebook.net/en_US/all.js'</script>
<script type='text/javascript'>
window.fbAsyncInit = function() {
FB.init({appId:'".$appid."', status: true, cookie: true, xfbml: true});
FB.Canvas.setSize({ width: 800 , height: 860 , });
// ^ extra comma here
};
</script>
This sounds to me like a script that was pulled in with src, and loaded just halfway, causing a syntax error sine the remainder is not loaded.
IE7 has problems with arrays of objects
columns: [
{
field: "id",
header: "ID"
},
{
field: "name",
header: "Name" , /* this comma was the problem*/
},
...
Another variation of this bug: I had a function named 'continue' and since it's a reserved word it threw this error. I had to rename my function 'continueClick'
Maybe you've got an object having a method 'constructor' and try to invoke that one.
You may hit this problem while using Knockout JS. If you try setting class attribute like the example below it will fail:
<span data-bind="attr: { class: something() }"></span>
Escape the class string like this:
<span data-bind="attr: { 'class': something() }"></span>
My 2 cents.
I too had come across this issue. I found below two solutions.
1). Same as mentioned by others above, remove extra comma from JSON object.
2). Also, My JSP/HTML was having . Because of this it was triggering browser's old mode which was giving JS error for extra comma. When used it triggers browser's HTML5 mode(If supported) and it works fine even with Extra Comma just like any other browsers FF, Chrome etc.
Here is a easy technique to debug the problem:
echo out the script/code to the console.
Copy the code from the console into your IDE.
Most IDE's perform error checking on the code and highlight errors.
You should be able to see the error almost immediately in your JavaScript/HTML editor.
Had the same issue with a different configuration. This was in an angular factory definition, but I assume it could happen elsewhere as well:
angular.module("myModule").factory("myFactory", function(){
return
{
myMethod : function() // <--- error showing up here
{
// method definition
}
}
});
Fix is very exotic:
angular.module("myModule").factory("myFactory", function(){
return { // <--- notice the absence of the return line
myMethod : function()
{
// method definition
}
}
});
This can also happen in Typescript if you call a function in middle of nowhere inside a class. For example
class Dojo implements Sensei {
console.log('Hi'); // ERROR Identifier expected.
constructor(){}
}
Function calls, like console.log() must be inside functions. Not in the area where you should be declaring class fields.
Typescript for Windows issue
This works in IE, chrome, FF
export const OTP_CLOSE = { 'outcomeCode': 'OTP_CLOSE' };
This works in chrome, FF, Does not work in IE 11
export const OTP_CLOSE = { outcomeCode: 'OTP_CLOSE' };
I guess it somehow related to Windows reserved words