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String cutting with Javascript

I have a string like "home/back/step" new string must be like "home/back".
In other words, I have to remove the last word with '/'. Initial string always has a different length, but the format is the same "word1/word2/word3/word4/word5...."

var x = "home/back/step";
var splitted = x.split("/");
splitted.pop();
var str = splitted.join("/");
console.log(str);
Take the string and split using ("/"), then remove the last element of array and re-join with ("/")

Use substr and remove everything after the last /
let str = "home/back/step";
let result = str.substr(0, str.lastIndexOf("/"));
console.log(result);

You could use arrays to remove the last word
const text = 'home/back/step';
const removeLastWord = s =>{
let a = s.split('/');
a.pop();
return a.join('/');
}
console.log(removeLastWord(text));

Seems I got a solution
var s = "your/string/fft";
var withoutLastChunk = s.slice(0, s.lastIndexOf("/"));
console.log(withoutLastChunk)

You can turn a string in javascript into an array of values using the split() function. (pass it the value you want to split on)
var inputString = 'home/back/step'
var arrayOfValues = inputString.split('/');
Once you have an array, you can remove the final value using pop()
arrayOfValues.pop()
You can convert an array back to a string with the join function (pass it the character to place in between your values)
return arrayOfValues.join('/')
The final function would look like:
function cutString(inputString) {
var arrayOfValues = inputString.split('/')
arrayOfValues.pop()
return arrayOfValues.join('/')
}
console.log(cutString('home/back/step'))

You can split the string on the '/', remove the last element with pop() and then join again the elements with '/'.
Something like:
str.split('/');
str.pop();
str.join('/');
Where str is the variable with your text.

Get values from string through RegEx

I'm trying to get size values from a strings, which looks like:
https://example.com/eb5f16e5-9b3d-cfcd-19b0-75c6ace724e1/size/80x90/center/
I'm using match method and following RegEx:
'...'.match(/\/(\d+)x(\d+)\//g)
I hoped that the parentheses help to highlight the numbers:
But match returns only ["/80x90/"] without separate size values, like ["/80x90/", "80", "90"].
What am I'm doing wrong?
Here you can test my RegEx.

You don't need g modifier, without it you can get matching groups:
var url = 'https://example.com/eb5f16e5-9b3d-cfcd-19b0-75c6ace724e1/size/80x90/center/';
var res = url.match(/\/(\d+)x(\d+)\//);
console.log(res);

RegExp#exec will return all the captured group including the captured subexpression.
var url = 'https://example.com/eb5f16e5-9b3d-cfcd-19b0-75c6ace724e1/size/80x90/center/';
var patt = /\/(\d+)x(\d+)\//g;
var result = [];
while ((result = patt.exec(url)) !== null) {
console.log(result);
}

Using RegExp to substring a string at the position of a special character

Suppose I have a sting like this: ABC5DEF/G or it might be ABC5DEF-15 or even just ABC5DEF, it could be shorter AB7F, or AB7FG/H.
I need to create a javascript variable that contains the substring only up to the '/' or the '-'. I would really like to use an array of values to break at. I thought maybe to try something like this.
...
var srcMark = array( '/', '-' );
var whereAt = new RegExp(srcMark.join('|')).test.str;
alert("whereAt= "+whereAt);
...
But this returns an error: ReferenceError: Can't find variable: array
I suspect I'm defining my array incorrectly but trying a number of other things I've been no more successful.
What am I doing wrong?

Arrays aren't defined like that in JavaScript, the easiest way to define it would be with:
var srcMark = ['/','-'];
Additionally, test is a function so it must be called as such:
whereAt = new RegExp(srcMark.join('|')).test(str);
Note that test won't actually tell you where, as your variable suggests, it will return true or false. If you want to find where the character is, use String.prototype.search:
str.search(new RegExp(srcMark.join('|'));
Hope that helps.

You need to use the split method:
var srcMark = Array.join(['-','/'],'|'); // "-|/" or
var regEx = new RegExp(srcMark,'g'); // /-|\//g
var substring = "222-22".split(regEx)[0] // "222"
"ABC5DEF/G".split(regEx)[0] // "ABC5DEF"

From whatever i could understand from your question, using this RegExp /[/-]/ in split() function will work.
EDIT:
For splitting the string at all special characters you can use new RegExp(/[^a-zA-Z0-9]/) in split() function.
var arr = "ABC5DEF/G";
var ans = arr.split(/[/-]/);
console.log(ans[0]);
arr = "ABC5DEF-15";
ans = arr.split(/[/-]/);
console.log(ans[0]);
// For all special characters
arr = "AB7FG/H";
ans = arr.split(new RegExp(/[^a-zA-Z0-9]/));
console.log(ans[0]);

You can use regex with String.split.
It will look something like that:
var result = ['ABC5DEF/G',
'ABC5DEF-15',
'ABC5DEF',
'AB7F',
'AB7FG/H'
].map((item) => item.split(/\W+/));
console.log(result);
That will create an Array with all the parts of the string, so each item[0] will contain the text till the / or - or nothing.

If you want the position of the special character (non-alpha-numeric) you can use a Regular Expression that matches any character that is not a word character from the basic Latin alphabet. Equivalent to [^A-Za-z0-9_], that is: \W
var pattern = /\W/;
var text = 'ABC5DEF/G';
var match = pattern.exec(text);
var position = match.index;
console.log('character: ', match[0]);
console.log('position: ', position);

How can I capture word by Regex

I would like to capture the array key from a string.
Here are my words: message[0][generic][0][elements][0][default_action][url]...
I want to capture the array keys after message[0][generic][0][elements][0], and the expected results are default_action and url etc.
I have tried following patterns but not work.
message\[0\]\[generic\]\[0\]\[elements\]\[0\](?=\[(\w+)\]): it captures default_action only;
\[(\w+)\]: it captures all array keys, but includes 0, generic, elements...
Is there any regex pattern for JavaScript that make the result array inverse, like [url, default_action]?

You can replace unwanted part of a string,and then get all other keys.
var string = 'message[0][generic][0][elements][0][default_action][url][imthird]';
var regexp = /message\[0\]\[generic\]\[0\]\[elements\]\[0\]/
var answer = string.replace(regexp,'').match(/[^\[\]]+/g)
console.log(answer);

To extract any number of keys and reverse the order of the elements in resulting array:
str = "message[0][generic][0][elements][0][default_action][url]";
res = str.match(/\[([^\d\]]+)\](?=\[[^\d\]]*\]|$)/g)
.map(function(s) { return s.replace(/[\[\]]/g, "") })
.reverse();
console.log(res);

The solution using String.prototype.split() and Array.prototype.slice() functions:
var s = 'message[0][generic][0][elements][0][default_action][url]...',
result = s.split(/\]\[|[\[\]]/g).slice(-3,-1);
console.log(result);

Storing The Sliced Character from .slice Method

When I utilise the slice method like so:
"Hello".slice(0,-1);
The result I get will be "Hell". Then if I run through that again using the same code, I will get "Hel".
Is there a way that I can extract and store into a variable the actual character that was sliced off, in this case "H" or on the second run "e", and not just the remainder of the string?

You could just use a second .slice() on the original string.
For example, where "Hello".slice(0,-1); returns all but the last character, "Hello".slice(-1) returns only the last character.
var input = "Hello";
var removed = input.slice(-1); // "o"
var remaining = input.slice(0, -1); // "Hell"
I don't think there's a more generic solution than that, because .slice() also lets you extract the middle of a string, in which case you'd need two extra calls to get the two parts being removed.
Demo:
var input = "Hello";
var allRemoved = [];
var removed;
while (input != "") {
allRemoved.push(removed = input.slice(-1));
input = input.slice(0, -1);
console.log("'" + removed + "' removed, leaving '" + input + "'");
}
console.log("Removed: " + allRemoved.join(", "));
Alternatively, if you only care about removing characters one at a time, you could forget about .slice() and instead convert the string to an array and use .shift() or .pop() to remove the character at the beginning or end respectively:
var input = "Hello";
var inArr = input.split("");
while (inArr.length > 0) {
console.log(inArr.pop());
}

This might not be the most efficient way to do this but you can turn yout string as an array with .split, then use .splice to remove certain elements ( letters ) and store them as a variable. Finally you turn your variable of removed letters back to a string using .join
let name = 'David'
let arrayname = name.split('')
let chosenLetters = arrayname.splice(0,2)
let finalLetters = chosenLetters.join('')
console.log(finalLetters) //should output Da
For split and join I recommend you leave the argument as (''). For .splice you can find in the docs for js how to select specific letters. In my example I am saying "Start at index 0 and cut the first 2 elements". Splice has many other ways to select an index so I recommend you read the docs.
In one line of code it can be generalized to :
let name = 'David'
let finalLetters = name.split('').splice(0,2).join('')
console.log(finalLetters) //should output Da