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 ma 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.

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 ma 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.

• javascript
• string

• 1 Regarding your second snippet: "And that didn't return anything"... it clearly does: jsfiddle/wxprm41z – Gerardo Furtado Commented Apr 15, 2019 at 2:33
• 2 Here is an image to show you (answering to your now deleted ment): imgur./UZTF6Be. – Gerardo Furtado Commented Apr 15, 2019 at 2:39
• So then my second guess was actually working. I don't know why it wasn't logging anything to the console before. – HappyHands31 Commented Apr 15, 2019 at 2:42
• Yes, it was working. So, at the end, your question was unnecessary! What strikes me the most is that 3 high-rep users saw your question, saw that you had a working code (I hope so...) but, instead of voting to close and leave you a ment, decided to write an answer. – Gerardo Furtado Commented Apr 15, 2019 at 3:14
• 1 @GerardoFurtado I'm going to go ahead and delete this question. The question that I linked already has the correct answer with (0, longDate.indexOf(",")). – HappyHands31 Commented Apr 15, 2019 at 14:34

3 Answers 3

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"))

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"))

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

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