Develop Reference

DiscordJS: Check if input is in a string

Hello!
I will try to do my best as possible to explain this issue i have.
A bin with some of the code mentioned, with comments:
Codebin
I am currently working on a Discord bot, where there is data stored in a .json file (As string).
Maybe this should be converted to an array instead?
A user writes a command and the bot initializes a sequence where it will go through several options depending on whats found in the string.
I've been struggling with this far too long (atleast 10 hours now & i am severely out of ideas now) on getting a check in for user response, to see if the input he does is in the array.
If i write !color 76561197458345 - it starts the process as seen below:
As you see the Available Options for found Dino (Carnotaurus) is:
[Utah1, Utah2]
Which is correct since its listed as the detailcrest options for Carnotaurus below in my json
[
{
"name": "Acrocanthosaurus",
"detailcrest": "[Utah1, Utah2]",
"underbelly": "[Utah3, Utah4]",
"body1": "[Utah5, Utah6]",
"body2": "[Utah7, Utah8]",
"body3": "[Utah9, Utah10]"
},
{
"name": "Carnotaurus",
"detailcrest": "[Utah1, Utah2]",
"underbelly": "[Utah3, Utah4]",
"body1": "[Utah5, Utah6]",
"body2": "[Utah7, Utah8]",
"body3": "[Utah9, Utah10]"
}
]
What then happens is that the user is gonna give a input based on the options found (This case Utah1, Utah2).
I want the bot to check the response from user in chat, if his answer is existing in the json file.
If respond to the bot in chat with Utah1 - it would proceed to next question (Because it exists).
If respond to the bot in chat with Pizza2 - it would respond (Not found, please select available options)
TL;DR:
I simply need a way to check if user response (word) is existing in the string
If Yes: continue, If No: error
I hope someone can give tips, or atleast push in the right direction on how to procceed with this.

I found a simple, but obviously not the most smart answer to my own solution - however it works as expected.
I've changed my .json strings to simply not include any brackets
"detailcrest": "Utah1, Utah2",
To search through my string i applied a .split() function (to seperate words with ,)
const inputCheck = color.detailcrest.toLowerCase().split(',').includes(detailcrest);
If i then do a if else statement on it, it returns true or false - for the given input, if it exists in the json file.
if (inputCheck === true) {
console.log("found")
} else {
console.log("False")
}
Obviously this wouldn't be the smartest way to proceed in a professional
But in my little bot it should work out with what is expected.
Due to limits, i will accept my own answer as solution in two days.

Javascript: How can I use object properties in functions using the parameter?

I am a beginner to Javascript and I am trying to make a text-based game for practice. I have made objects for enemies like so:
export const spider = {
strength: 1,
health: 4,
gold: 1
};
I am now trying to make a function which can search for their stats when their name is entered in the field. It looks like this:
export const findStats = (target) => {
return target.health;
}
However, when I do this and test it I get 'undefined.' However, if I replace 'target.health' with 'spider.health' it works properly.
The error occurs when I try doing findStats("spider") which gives me the 'undefined results.'
Any help would be appreciated. Note: I did look around this site but found the threads too complex or not quite what I was looking for. I am a beginner so simple terms would be greatly appreciated!
Thanks for all your comments!
My issue is unlike to the one on the right as when I try it with my code is still returns 'undefined.' Here is the code that I have just tried using the other thread. Keep in mind I am a beginner so I am probably doing it very wrong but if you could help further I would be very happy.
export const findLocalStats = (target) => {
var bar = 'strength';
console.log(target[bar]);
}
Here are is my test command:
expect(findLocalStats("spider")).toEqual(1);
Furthermore, when I tried the code written in JSFiddle in my editor, it still gave the same error in the terminal which is 'undefined.'
export function findStats(target) {
return target.strength;
}
And the test command:
expect(findStats("spider")).toEqual(1);
And the exact error message:
findStats() gives the stats of the target wanted.
expect(received).toEqual(expected)
Expected value to equal:
1
Received:
undefined
Difference:
Comparing two different types of values. Expected number but received undefined.
Sorry if this is very tedious.
Note 2: I posted this question before but I have changed it to attempt to explain my issue better as I still do not understand the answers I was given and the links to duplicate questions - which I have tried to replicate. Furthermore, the duplicate that I was given was different. It used the object as the keyword, however I want to use it as a feed-in to a parameter so that it is versatile for more than one enemies if that makes sense. Thank you!

When you are calling findStats like this : findStats("spider") you are sending a string to the function as an argument. That's why when it tries to get the property health it says undefined.
You need to give the function an instance of your spider object. To create an instance you can use the Object.create() method like var killMe = Object.create(spider). This will create a new object based on the one you declared before. Then you can call your function like this : findStats(killMe)
You can find an exemple here : https://jsfiddle.net/10ex1xqt/

.deny Meteor use.. can't get it to work

I'm trying to deny a question to be submitted if it has a length of 0. But I don't quite understand Meteor deny.
Here's what's going on.
I am updating the question. It is currently set at "yes"
I update it to "yessir"
I console log it as follows:
Questions.deny({
update: function(userId, question) {
console.log(question.question.length);
}
});
but the result is 3. It seems to console log the field being updated, not what I am updating it TO.
This is a problem because how can I check the length of an input if this thing won't check it when it's being submitted.
Can someone enlighten me?

Have a look at the docs and you'll see that the 2nd argument to update is doc:
doc is the current version of the document from the database, without the proposed update
The only way to validate the length of question is to look at the 4th argument - modifier. The problem with this approach is that you must check the modifier for every possible way it could be modified. Fundamentally, this is why allow/deny is really hard to implement in all but the most simple cases.
Instead, I'd strongly suggest either using collection2 to enforce your schema or using methods to modify your documents.
Recommended reading:
Meteor method vs. deny/allow rules
Allow & Deny: A Security Primer

Collection.deny Function either returns true or flase.
If you want to deny update on certain criteria here goes your code like this
Questions.deny({
update: function(userId, question, fields, modifier) {
// check for critera
if(fields.question.length < 0)
return true // denys update for question length less than 0
else
return false // deny = false means allow = true
}
});

very slow filters with couchDB even with erlang

I have a database (couchDB) with about 90k documents in it. The documents are very simple like this:
{
"_id": "1894496e-1c9e-4b40-9ba6-65ffeaca2ccf",
"_rev": "1-2d978d19-3651-4af9-a8d5-b70759655e6a",
"productName": "Cola"
}
now I want one day to sync this database with a mobile device. Obviously 90k docs shouldn't go to the phone all at once. This is why I wrote filter functions. These are supposed to filter by "productName". At first in Javascript later in Erlang to gain performance. These Filter functions look like this in JavaScript:
{
"_id": "_design/local_filters",
"_rev": "11-57abe842a82c9835d63597be2b05117d",
"filters": {
"by_fanta": "function(doc, req){ if(doc.productName == 'Fanta'){ return doc;}}",
"by_wasser": "function(doc, req){if(doc.productName == 'Wasser'){ return doc;}}",
"by_sprite": "function(doc, req){if(doc.productName == 'Sprite'){ return doc;}}"
}
}
and like this in Erlang:
{
"_id": "_design/erlang_filter",
"_rev": "74-f537ec4b6508cee1995baacfddffa6d4",
"language": "erlang",
"filters": {
"by_fanta": "fun({Doc}, {Req}) -> case proplists:get_value(<<\"productName\">>, Doc) of <<\"Fanta\">> -> true; _ -> false end end.",
"by_wasser": "fun({Doc}, {Req}) -> case proplists:get_value(<<\"productName\">>, Doc) of <<\"Wasser\">> -> true; _ -> false end end.",
"by_sprite": "fun({Doc}, {Req}) -> case proplists:get_value(<<\"productName\">>, Doc) of <<\"Sprite\">> -> true; _ -> false end end."
}
}
To keep it simple there is no query yet but a "hardcoded" string. The filter all work. The problem is they are way to slow. I wrote a testprogram first in Java later in Perl to test the time it takes to filter the documents. Here one of my Perl scripts:
$dt = DBIx::Class::TimeStamp->get_timestamp();
$content = get("http://127.0.0.1:5984/mobile_product_test/_changes?filter=local_filters/by_sprite");
$dy = DBIx::Class::TimeStamp->get_timestamp() - $dt;
$dm = $dy->minutes();
$dz = $dy->seconds();
#contArr = split("\n", $content);
$arraysz = #contArr;
$arraysz = $arraysz - 3;
$\="\n";
print($dm.':'.$dz.' with '.$arraysz.' Elements (JavaScript)');
And now the sad part. These are the times I get:
2:35 with 2 Elements (Erlang)
2:40 with 10000 Elements (Erlang)
2:38 with 30000 Elements (Erlang)
2:31 with 2 Elements (JavaScript)
2:40 with 10000 Elements (JavaScript)
2:51 with 30000 Elements (JavaScript)
btw these are Minutes:Seconds. The number is the number of elements returned by the filter and the database had 90k Elements in it. The big surprise was that the Erlang filter was not faster at all.
To request all elements only takes 9 seconds. And creating views about 15. But it is not possible for my use on a phone to transfer all documents (volume and security reasons).
Is there a way to filter on a view to get a performance increase?
Or is something wrong with my erlang filter functions (I'm not surprised by the times for the JavaScript filters).
EDIT:
As pointed out by pgras the reason why this is slow is posted in the answer to this Question. To have the erlang filters run faster I need to go a "layer" below and program the erlang directly into the database and not as a _design document. But I dont'r really know where to start and how to do this. Any tips would be helpful.

This has been a while since I asked this question. But I thought I would come back to it and share what we ended up doing to solve this.
So the short answer is filter speed can't really be improved.
The reason is behind the way filters work. If you check your database changes. They are here:
http://<ip>:<port>/<databaseName>/_changes
This document contains all changes belonging to your database. If you do anything in your database new lines are just added. When one now wants to use a filter the filter is parsed from json to the specified language and used for every line in this file. To be clear as far as I am aware the parsing is done for each line as well. This is not very efficient and can't be changed.
So I personally think for most use cases filter are to slow and can't be used. This means we have to find a way around this. I do not imply that I have a general solution. I can just say that for us here it was possible to use views instead of filter. Views generate trees internally and are as fast as light compared to filter. A Simple filter is also stored in design document and could look like this:
{
"_id": "_design/all",
"language": "javascript",
"views": {
"fantaView": {
"map": "function(doc) { \n if (doc.productName == 'Fanta') \n emit(doc.locale, doc)\n} "
}
}
}
Where fantaView is the name for the view. I guess the function is self explanatory. So this is what we did I hope it helps someone if he runs into a similar issue.

I may be wrong but filter functions should return boolean values so try to change one to:
function(doc, req){ return doc.productName === 'Fanta';}
It may solve your performance problem...
Edit:
Here is an explanation about why it is slow (at least with JavaScript)...
One solution would be to use a view to select the ids of the documents to sync and then to start the sync by specifying the doc_ids to sync.
For example the view would be:
function(doc){
emit(doc.productName, doc._id)
}
You could call the view with _design/docs/_view/by_producName?key="Fanta"
And then start the replication with the found doc ids...

In general couchDB filters are slow. Others have already explained why they are slow. What I found was that the only reasonable way to use filters are to use the "since". Otherwise in a reasonably large database (mine has 47k docs, and they are complex docs) filters don't work. We learnt this the hard way by migrating from dev to prod [few hundred docs to ~47k docs]. We also changed design to a query a view and because we required a continuous feed like behaviour, we used Spring's #Scheduled

JSLint "eval is evil." alternatives

I am have some JavaScript functions that run on both the client (browser) and the server (within a Java Rhino context). These are small functions - basically little validators that are well defined and don't rely upon globals or closures - self-contained and portable.
Here's an example:
function validPhoneFormat(fullObject, value, params, property) {
var phonePattern = /^\+?([0-9\- \(\)])*$/;
if (value && value.length && !phonePattern.test(value))
return [ {"policyRequirement": "VALID_PHONE_FORMAT"}];
else
return [];
}
To keep things DRY, my server code gets a handle on each of these functions and calls toString() on them, returning them to the browser as part of a JSON object. Something like this:
{ "name" : "phoneNumber",
"policies" : [
{ "policyFunction" : "\nfunction validPhoneFormat(fullObject, value, params, property) {\n var phonePattern = /^\\+?([0-9\\- \\(\\)])*$/;\n if (value && value.length && !phonePattern.test(value)) {\n return [{\"policyRequirement\":\"VALID_PHONE_FORMAT\"}];\n } else {\n return [];\n }\n}\n"
}
]
}
My browser JS code then takes this response and creates an instance of this function in that context, like so:
eval("var policyFunction = " + this.policies[j].policyFunction);
policyFailures = policyFunction.call(this, form2js(this.input.closest("form")[0]), this.input.val(), params, this.property.name));
This all works very well. However, I then run this code through JSLint, and I get back this message:
[ERROR] ValidatorsManager.js:142:37:eval is evil.
I appreciate that often, eval can be dangerous. However, I have no idea how else I could implement such a mechanism without using it. Is there any way I can do this and also pass through the JSLint validator?

I wouldn't worry about it since you are only passing these function strings from the server to the client, and are thus in control of what will be evaluated.
On the other hand, if you were going the other direction and doing the evals of client-passed code on the server, that would be an entirely different story...
Update:
As disabling the validation option in your comment may cause you to miss future errors, I would instead suggest passing the function name rather than the entire function and have the function library mirrored on the server and client. Thus, to call the function, you'd use the following code:
var policyFunction = YourLibraryName[this.policies[j].policyFunctionName];
var policyArguments = this.policies[j].policyArguments;
policyFunction.apply(this, policyArguments);
Update 2:
I was able to validate the following code with JSLint successfully, which essentially allows you to "turn off" validation for the vast minority of cases where eval is appropriate. At the same time, JSLint still validates normal eval calls, and all uses of this method should throw up flags for future developers to avoid using it/refactor it out where possible/as time allows.
var EVAL_IS_BAD__AVOID_THIS = eval;
EVAL_IS_BAD__AVOID_THIS(<yourString>);

Dont encode a function as a string in JSON. JSON is for content, which you are confounding with behavior.
Instead, I suppose you could return JS files instead, which allow real functions:
{ name : "phoneNumber",
policies : [
{ policyFunction : function() {
whateverYouNeed('here');
}
}
]
}
But while that solves the technical issue, it's still not a great idea.
The real solution here is to move your logic out of your content entirely. Import a JS file full of little validation functions and call them as needed based on a dataType property in your JSON or something. If this functions are as small and portable as you say, this should be trivial to accomplish.
Getting your data all tangled up with your code usually leads to pain. You should statically include your JS, then dynamically request/import/query for your JSON data to run through your statically included code.

I would avoid using eval in all situations. There's no reason you can't code around it. Instead of sending code to the client, just keep it hosted on the server in one contained script file.
If that's not doable, you can also have a dynamically generated javascript file then pass in the necessary parameters via the response, and then dynamically load the script on the client side. There's really no reason to use eval.
Hope that helps.

You can use
setInterval("code to be evaluated", 0);
Internally, if you pass setInterval a string it performs a function similar to eval().
However, I wouldn't worry about it. If you KNOW eval() is evil, and take appropriate precautions, it's not really a problem. Eval is similar to GoTo; you just have to be careful and aware of what you're doing to use them properly.

With very little parsing you could have had it like so:
var body = this.policies[j].policyFunction.substr;
body = body.substr(body.indexOf("(") + 1);
var arglist = body.substr(1, body.indexOf(")"));
body = body.substr(arglist.length + 1);
var policyFunction = new Function(arglist, body);
Which would provide a bit of validation, avoid the literal use of eval and work synchronously with the code. But it is surely eval in disguise, and it is prone to XSS attack. If the malevolent person can get their code loaded and evaluated this way - it will not save you. So, really, just don't do it. Add a <script> tag with the proper URL and that would be certainly safer. Well, you know, better safe then sorry.
PS. My apologises if the code above doesn't work, it only shows the intent, I've not tested it, and if I made a mistake at counting parenthesis or some such - well, you should get the idea, I'm not advertising it by any means.

DRY is definitely something I agree with, however there is a point where copy+pasting is more efficient and easy to maintain than referencing the same piece of code.
The code you're saving yourself from writing seems to be equivalent to a clean interface, and simple boiler plate. If the same code is being used on both the server and the client, you could simply pass around the common pieces of the function, rather than the whole function.
Payload:
{
"name": "phoneNumber",
"type": "regexCheck",
"checkData": "/^\\+?([0-9\\- \\(\\)])*$/"
}
if(payload.type === "regexCheck"){
const result = validPhoneFormat(fullObject, value, payload.checkData)
}
function validPhoneFormat(fullObject, value, regexPattern) {
if (value && value.length && !regexPattern.test(value))
return [ {"policyRequirement": "VALID_PHONE_FORMAT"}];
else
return [];
}
This would give you the ability to update the regex from a single location. If the interface changes it does need to be updated in 2 places, but I wouldn't consider that a bad thing. If the client is running code, why hide the structure?
If you really, really want to keep both the object structure and the patterns in one place - extract it to a single API. Have a "ValidatePhoneViaRegex" api endpoint which is called by all places you'd be passing this serialized function to.
If all of this seems like too much effort, set jslint to ignore your piece of code:
"In JSHint 1.0.0 and above you have the ability to ignore any warning with a special option syntax. The identifier of this warning is W061. This means you can tell JSHint to not issue this warning with the /*jshint -W061 */ directive.
In ESLint the rule that generates this warning is named no-eval. You can disable it by setting it to 0, or enable it by setting it to 1."
https://github.com/jamesallardice/jslint-error-explanations/blob/master/message-articles/eval.md
I would prefer to see copy+pasted code, a common api, or receiving parameters and copy+pasted boiler plate than magical functions passed in from the server to be executed.
What happens if you get a cross-browser compatibility error with one of these shared functions?

Well, the first thing to bear in mind is that jsLint does make the point that "it will hurt your feelings". It's designed to point out where you're not following best practices -- but code that isn't perfect can still work just fine; there's no compulsion upon you to follow jsLint's advice.
Having said that, eval is evil, and in virtually all cases there is always a way around using it.
In this case, you could use a library such as require.js, yepnope.js or some other library that is designed to load a script separately. This would allow you to include the javascript functions you need dynamically but without having to eval() them.
There are probably several other solutions as well, but that was the first one that came to my mind.
Hope that helps.