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search if string exists in any value of array like indexOf

I have a cookie split into an array:
var cooks = document.cookie.split(';');
[dogs=bla, cats=sdfgh, cabbages=kjhgfdfg]
If I wanted to find the index of 'cats=sdfgh' I could use
cooks.indexOf('cats=sdfgh');
1
But if I wanted to search to see if the value cats has been set, how would I do that? cooks.indexOf(find('cat=')); or something to that effect?
So without knowing the value of cats, how can I tell if it exists in the cookie?
And, how can I get the index number of that cookie?

you could run a simple regular expression:
if(fun = document.cookie.match(/(^cats=|;cats=)([^;]+)/)){
console.log(fun);
}
it will give you an array where the 3rd member is your value if it matches :)
JSFIDDLE
However, if you dont have to support shitty browsers its worth taking a look at the the MDN cookie framework referenced in the comments.

You can use Array.prototype.some method to find the first matching value in array:
var cooks = document.cookie.split(';'); // ["dogs=bla", "cats=sdfgh", "cabbages=kjhgfdfg"]
var isSet = cooks.some(function(cookie) {
return cookie.indexOf('cats') == 0;
}); // => true

AngularJS soltuion to determining if any element in array1 exists in array2

I am working on an angularJS widget (my first) and I currently am looking for an angularJS solution to my problem.
Basically I have one array containing a list of string values.
var array1 = [
"Need to Know",
"Test Category 2",
"News"
];
and another array containing another list of string values
var array2 = [
"need to know",
"release notes",
"NEWS"
];
I need a true statement if any element from one array matches any element from the other array. The result also needs to be case insensitive.
Here is my current solution and works great.
angular.module("myWidget", function(...){
// angular code here
})
.service('arrayService', function() {
function arrayToLowerCase(array) {
return array.join("~!~").toLowerCase().split("~!~");
}
function arrayElementIsInArray(array1, array2) {
for (var i in array1) {
if (array2.indexOf(array1[i]) >= 0) {
return true;
}
}
return false;
}
function arrayCompare(array1, array2) {
return arrayElementIsInArray(arrayToLowerCase(array1), arrayToLowerCase(array2));
}
return {
arrayToLowerCase: arrayToLowerCase,
arrayElementIsInArray: arrayElementIsInArray,
arrayCompare: arrayCompare
};
})
the problem is my javascript coders (I primary work in c#) feel there is a more angularJS way to do this but they have brought nothing to the table as a definitive solution. It was suggested that the $filter module might be useful but I didn't see how it would exactly solve my problem.
If I already have the best solution, then awesome. If not please let me know what you think and lets go from there.
Thanks in advance.
EDIT: In response to some of the answers, I felt that I might have misinterpreted my request. What I am asking is there a built in function that angular provides that does this out of the box?
After researching this a bit more; the $filter Module will probably do it with a custom comparater implemented but that seems like way overkill for what I am looking for.
The current responses are all good stuff though. Thanks again!

Absolutely nothing to do with Angular. This is plain data structures and data manipulation. To say there should be a more AngularJS way of doing it would be like saying there should be a more MVC way to add two numbers.
Angular provides no basic data structures and utility set of functions beyond what is available in your browser's native list of array functions, which is different depending on which ECMAScript standard the browser supports.
You may want to look into a library like Lo-Dash for stuff like this (which you can use right along with Angular with no problems) as it's preferable to have proven code for these kind of data manipulations than to constantly have to debug your own.
With Lo-Dash, and remembering the requirement for case-insensitivity:
var array1Lowered = _.map(array1, function (value) { return value.toLowerCase(); });
var anyMatchesBool = _.any(array2, function (value) {
return _.contains(array1Lowered, value);
});
Note that I'm making the assumption that there will be no non-string items in either array.
Lo-Dash normalizes the API so you don't need to worry about what functions each browswer supports. If there's a native function, Lo-Dash will use it because it's faster. If not, Lo-Dash provides an all-JavaScript implementation.

Try this on for size. To me this really has nothing to do with Angular
(function(array1, array2) {
var tlc = function(a) { return a.toLowerCase(); };
array2 = array2.map(tlc);
array1 = array1.map(tlc);
return array1.filter(function(n) {
return array2.indexOf(n) != -1;
}).length > 0;
})(array1, array2);

Using native functions...
var intersection = array1.filter(function(n) {
return array2.indexOf(n) != -1
});
With help from Simplest code for array intersection in javascript

How to make indexOf only match 'hi' as a match and not 'hirandomstuffhere'?

Basically I was playing around with an Steam bot for some time ago, and made it auto-reply when you said things in an array, I.E an 'hello-triggers' array, which would contain things like "hi", "hello" and such. I made so whenever it received an message, it would check for matches using indexOf() and everything worked fine, until I noticed it would notice 'hiasodkaso', or like, 'hidemyass' as an "hi" trigger.
So it would match anything that contained the word even if it was in the middle of a word.
How would I go about making indexOf only notice it if it's the exact word, and not something else in the same word?
I do not have the script that I use but I will make an example that is pretty much like it:
var hiTriggers = ['hi', 'hello', 'yo'];
// here goes the receiving message function and what not, then:
for(var i = 0; i < hiTriggers.length; i++) {
if(message.indexOf(hiTriggers[i]) >= 0) {
bot.sendMessage(SteamID, randomHelloMsg[Math stuff here blabla]); // randomHelloMsg is already defined
}
}
Regex wouldn't be used for this, right? As it is to be used for expressions or whatever. (my English isn't awesome, ikr)
Thanks in advance. If I wasn't clear enough on something, please let me know and I'll edit/formulate it in another way! :)

You can extend prototype:
String.prototype.regexIndexOf = function(regex, startpos) {
var indexOf = this.substring(startpos || 0).search(regex);
return (indexOf >= 0) ? (indexOf + (startpos || 0)) : indexOf;
}
and do:
var foo = "hia hi hello";
foo.regexIndexOf(/hi\b/);
Or if you don't want to extend the string object:
foo.substr(i).search(/hi\b/);
both examples where taken from the top answers of Is there a version of JavaScript's String.indexOf() that allows for regular expressions?

Regex wouldn't be used for this, right? As it is to be used for expressions or whatever. (my > English isn't awesome, ikr)
Actually, regex is for any old pattern matching. It's absolutely useful for this.
fmsf's answer should work for what you're trying to do, however, in general extending native objects prototypes is frowned upon afik. You can easily break libraries by doing so. I'd avoid it when possible. In this case you could use his regexIndexOf function by itself or in concert with something like:
//takes a word and searches for it using regexIndexOf
function regexIndexWord(word){
return regexIndexOf("/"+word+"\b/");
}
Which would let you search based on your array of words without having to add the special symbols to each one.

inArray() returns -1 even though element exists in array

$.post('service.php?getPhotos', function(data){
var photoIds = [];
$.each(data, function(){
photoIds.push(this.id);
});
console.log(_photoId); //7962669392
console.log(photoIds); //["7980686507", "7962669392", "7962163506"]
console.log($.inArray(_photoId, photoIds)); //-1
});
Why doesnt console.log($.inArray(_photoId, photoIds)); return 1?

string vs integer I would imagine. Different types would mean that inArray does not see them as the same. Make sure you are using a string instead of an integer and this should work.

It seems like _photoId is a number but photoIds contains strings. Try this:
$.inArray(''+ _photoId, photoIds)

This is because the $.inArray function also takes the type into account. It will not say that an integer is the same as a string. This is also explained in the first comment in the documentation.
You can use _photoId.toString() to get the string representation of the value.
Also note that ECMAScript (Javascript) have a native function called indexOf which does exactly the same thing as the jQuery one:
photoIds.indexOf(_photoId.toString())

fastest way to detect if a value is in a group of values in Javascript

I have a group of strings in Javascript and I need to write a function that detects if another specific string belongs to this group or not.
What is the fastest way to achieve this? Is it alright to put the group of values into an array, and then write a function that searches through the array?
I think if I keep the values sorted and do a binary search, it should work fast enough. Or is there some other smart way of doing this, which can work faster?

Use a hash table, and do this:
// Initialise the set
mySet = {};
// Add to the set
mySet["some string value"] = true;
...
// Test if a value is in the set:
if (testValue in mySet) {
alert(testValue + " is in the set");
} else {
alert(testValue + " is not in the set");
}

You can use an object like so:
// prepare a mock-up object
setOfValues = {};
for (var i = 0; i < 100; i++)
setOfValues["example value " + i] = true;
// check for existence
if (setOfValues["example value 99"]); // true
if (setOfValues["example value 101"]); // undefined, essentially: false
This takes advantage of the fact that objects are implemented as associative arrays. How fast that is depends on your data and the JavaScript engine implementation, but you can do some performance testing easily to compare against other variants of doing it.
If a value can occur more than once in your set and the "how often" is important to you, you can also use an incrementing number in place of the boolean I used for my example.

A comment to the above mentioned hash solutions.
Actually the {} creates an object (also mentioned above) which can lead to some side-effects.
One of them is that your "hash" is already pre-populated with the default object methods.
So "toString" in setOfValues will be true (at least in Firefox).
You can prepend another character e.g. "." to your strings to work around this problem or use the Hash object provided by the "prototype" library.

Stumbled across this and realized the answers are out of date. In this day and age, you should not be implementing sets using hashtables except in corner cases. You should use sets.
For example:
> let set = new Set();
> set.add('red')
> set.has('red')
true
> set.delete('red')
true
> set.has('red')
false
Refer to this SO post for more examples and discussion: Ways to create a Set in JavaScript?

A possible way, particularly efficient if the set is immutable, but is still usable with a variable set:
var haystack = "monday tuesday wednesday thursday friday saturday sunday";
var needle = "Friday";
if (haystack.indexOf(needle.toLowerCase()) >= 0) alert("Found!");
Of course, you might need to change the separator depending on the strings you have to put there...
A more robust variant can include bounds to ensure neither "day wed" nor "day" can match positively:
var haystack = "!monday!tuesday!wednesday!thursday!friday!saturday!sunday!";
var needle = "Friday";
if (haystack.indexOf('!' + needle.toLowerCase() + '!') >= 0) alert("Found!");
Might be not needed if the input is sure (eg. out of database, etc.).
I used that in a Greasemonkey script, with the advantage of using the haystack directly out of GM's storage.

Using a hash table might be a quicker option.
Whatever option you go for its definitely worth testing out its performance against the alternatives you consider.

Depends on how much values there are.
If there are a few values (less than 10 to 50), searching through the array may be ok. A hash table might be overkill.
If you have lots of values, a hash table is the best option. It requires less work than sorting the values and doing a binary search.

I know it is an old post. But to detect if a value is in a set of values we can manipulate through array indexOf() which searches and detects the present of the value
var myString="this is my large string set";
var myStr=myString.split(' ');
console.log('myStr contains "my" = '+ (myStr.indexOf('my')>=0));
console.log('myStr contains "your" = '+ (myStr.indexOf('your')>=0));
console.log('integer example : [1, 2, 5, 3] contains 5 = '+ ([1, 2, 5, 3].indexOf(5)>=0));

You can use ES6 includes.
var string = "The quick brown fox jumps over the lazy dog.",
substring = "lazy dog";
console.log(string.includes(substring));