Remove Everything After Certain Character Within String Using JavaScript

Question

EDIT : My code does work - I just had a typo when I was console.logging . It uses the same technique already found in the answer here .

I have a function that should remove everything after the comma in the string:

function shortenToDate(longDate) {

  let newDate = longDate.substring(0, longDate.indexOf(","));

  return newDate;

}

^ You just need to take a chunk out of the string from the 0 index to the indexOf() the first instance of whatever character you wish to remove everything after.

I had also tried:

function shortenToDate(longDate) {

  return longDate.substring(longDate.indexOf(0, ","));

}

console.log(shortenToDate(shortenToDate("Friday May 2, 9am")));

Which didn't have any effect. It just returned Friday May 2, 9am .

Answer 1

You can simply use split and take the 0 ^th index

 const shortenToDate = longDate => longDate.split(',',1)[0]; console.log(shortenToDate("Friday May 2, 9am")) 

Problems

In the first snippet you're using

longDate.substring(longDate.indexOf(","), longDate.length -1);

but you want from 0 ^th index

 const shortenToDate = longDate => longDate.substring(0,longDate.indexOf(",")); console.log(shortenToDate("Friday May 2, 9am")) 

Answer 2

How about that with String​.prototype​.split() and Array.prototype​.shift() ?

 function shortenToDate(longDate) { let newDate = longDate.split(','); return newDate.shift(); } console.log(shortenToDate("Friday May 2, 9am")) 

Answer 3

It would probably be easier to use a regular expression - match a comma, followed by any characters, and replace with the empty string:

 const shortenToDate = longDate => longDate.replace(/,.*/, ''); console.log(shortenToDate("Friday May 2, 9am"))