This question already has answers here:
What does this symbol mean in JavaScript?
(1 answer)
What's the meaning of "=>" (an arrow formed from equals & greater than) in JavaScript?
(14 answers)
Closed 2 years ago.
I m trying to picture this or trying to understand this but have a question whose answers i cannot find
const csv_to_array = (data, delimiter = ',', omitFirstRow = false) =>
.slice(omitFirstRow ? data.indexOf('\n') + 1 : 0)
.split('\n')
.map(v => v.split(delimiter));//Please explain this v thing thats confusing for me
console.log(csv_to_array('a,b\nc,d'));
Please help me in this case
Related
This question already has answers here:
Logical operators in JavaScript — how do you use them?
(2 answers)
What does the construct x = x || y mean?
(12 answers)
JavaScript OR (||) variable assignment explanation
(12 answers)
What does the comma operator do in JavaScript?
(5 answers)
Closed 13 days ago.
This post was edited and submitted for review 13 days ago and failed to reopen the post:
Original close reason(s) were not resolved
I am having trouble understanding this code
let txCount = transActions.reduce((count, item) => (count[item] = count[item] + 1 || 1, count), {});
I understand it is using the logical OR expression but what is "1,count" doing here and why does it work?
(count[item] = count[item] + 1 || 1, count)
This question already has answers here:
how to get url value after question mark in javascript
(2 answers)
Closed 3 years ago.
I have this simple code:
Subscribe today
when the user press on the a tag it takes him to the page subsc.php?English.
My question is how can i get the information after the ? (which is "English" in this example)?
You can try with Regex Positive Lookbehind /(?<=\?).$*/.
var url = '/subsc.php?English';
var r = url.match(/(?<=\?).*$/)[0];
console.log(r);
This question already has answers here:
What does the comma operator do in JavaScript?
(5 answers)
What does this symbol mean in JavaScript?
(1 answer)
Using &&'s short-circuiting as an if statement?
(6 answers)
Closed 4 years ago.
I have javascript code and I found the following line :
I'm a bit confused about the syntax
e = k.attr("data-icon"), e && (a.icon = e),
I understand the first part : k.attr("data-icon") but not the rest.
Can any one tell me what does that mean please ?
cheers,
This question already has answers here:
escaping question mark in regex javascript
(4 answers)
Closed 6 years ago.
I am new to javascript and have not much idea about regular expressions. Please help me in understanding the following code.
var r = new RegExp("^.*?https://www\\.facebook\\.com/servlet/SignOn.*$","i");
var content = "https://www.facebook.com/servlet/SignOn?msg=You+are+not+authorized+to+vie…r+level+of+authority.&cm_sp=TopNav-_-servlet-_-MMM&goto=MembersMainMenu%3F";
console.log(content.search(r));// It gives me 0
But when I change the regex to
var r = new RegExp("^.*?https://www\\.facebook\\.com/servlet/SignOn?msg=.*$","i");
console.log(content.search(r));// It gives me -1 , why??
n? means n is optional you need n\?
This question already has answers here:
What is the purpose of a plus symbol before a variable?
(4 answers)
Closed 6 years ago.
What does if (t == +t) { ... } mean?
Sorry for asking such a simple question, but I have searched for "plus operator" and tried to evaluate it in javascript myself, but I cannot guess what the purpose is.
Its a unary operator and it coerces t to a number from a string. It has the same effect as:
if (t == Number(t)) { ... }
For more information: Is plus sign in +process a typo in Node.js documentation on domains?