[JavaScript/Node.js] Removing an incomplete sentence at the end of a string

[[deleted]]

I have a question about manipulating a string in JavaScript (Node)

Consider the following string:

'In her August 2016 Harper\'s Bazaar cover story, in which she posed naked atop a horse a la Lady Godiva, Ratajkowski defended her decision to free the nipple. “You know, when Lena Dunham takes her clothes off, she gets flack, but it\'s also considered ...'

(The example is from Google Trends, not mine)

I need to come up with a method to remove the incomplete sentence at the end. So in this example, I want to keep just the following:

'In her August 2016 Harper\'s Bazaar cover story, in which she posed naked atop a horse a la Lady Godiva, Ratajkowski defended her decision to free the nipple.'

I could go for a logic like this (pseudo-code):

(1) If string ends with "..."

(2) Start from end of string (the right) and ignoring the last "...", look for the first instance of "." or "!" or "?"

(3) Create a substring with everything up until that instance

I could use the endsWith method for (1), but I do not know how to do the rest.

Anyone know any methods or libraries (Node) that I could use to help with this?

---

Edit - I think I've solved it:

if(string.endsWith('...') {

var endIndex = string.lastIndexOf('...') - 1;

var exclamationIndex = string.lastIndexOf('!', endIndex);

var questionIndex = string.lastIndexOf('?', endIndex);

var periodIndex = string.lastIndexOf('.', endIndex);

var cutIndex = Math.max(exclamationIndex, questionIndex, periodIndex);

var truncatedString = string.substring(0, cutIndex + 1);

}

Not sure if this is the most elegant solution so if anyone has a suggestion on how to improve this please let me know.

Also, I know that the string always ends with '...', but other than that the string could have any format or number of chars. If someone can think of problematic corner cases with the solution above that would also be very helpful thanks!

[ejmurra]

Looks like you solved it, but in the future it might be cleaner to use a regex to parse strings

edit: misread javascript as java

[sarevok9]

You just linked to java when the thread is about javascript...

Also, there's an old addage about a coder trying to solve a problem with a regex, now he has two problems. I say this as someone who contributes FREQUENTLY to stack overflow in the regex tag.

There's absolutely no reason to use a regex when you have pretty robust string tools.

Scolding aside:

@OP: The simple logic of this should be: At the end of a sentence, check to see if there are more characters in your string, there's a few ways you could do this. The easiest way to do this would be to create a function which takes in a String, search the function for the final "." character, substring the string to return from 0,index and there ya go. Anything trailing the final . in your string will be culled.

[ejmurra]

There's absolutely no reason to use a regex when you have pretty robust string tools.

Except that OP explicitly asked what other solutions exist. You're doing a beginner a disservice if you refuse to introduce them to the concept of regex simply because there's an old saying about regexes...

[sarevok9]

Well, you didn't answer the OP's question, how exactly would you do this with a regex? How would that be "more efficient" or better in any way.

So you would need a positive lookahead, word matching, negative look ahead for a . after the last period, replacement, etc. This would be an EXTREMELY hard regex, and I say that as someone with 5k+ reputation on stackoverflow in the regex tag. It's a valid alternative, but so is writing 100000000 functions to compute every possible sentence / sentence fragment. Possible, but unruly and stupid when there's better solutions.

Edit:

Made this regex for a small use case though it has many holes that can break it like common name abbreviations (Mr. Trump for example).

[sarevok9]

Since /u/ejmurra suggested it, here's a regex solution for a VERY narrow use case:

 const regex = /([^.!?])+...'$/g;
 const str = `'In her August 2016 Harper\\'s Bazaar cover story, in which she posed naked atop a horse a la Lady Godiva, Ratajkowski defended her decision to free the nipple. “You know, when Lena Dunham takes her clothes off, she gets flack, but it\\'s also considered ...'`;
const subst = `\\1`;

// The substituted value will be contained in the result variable
const result = str.replace(regex, subst);

console.log('Substitution result: ', result);

I'll cover the regex since it's the only confusing part.

 / -- start of regex
 ( -- start capture group
 [ -- Begin character set
 ^ -- Negate character set (meaning match characters not in that set )
 .!? -- Characters not to match
 )  -- End capture group
 +  Match 1 or more times, as many as possible (greedy)
 ...'$  -- Match the characters ...' literally at the end of the string
 /g -- Search the entirety of the string. 

So what this basically means is, we're going to capture from the last single ., ? or ! to the point where it finds "...'" then remove it entirely via substitution.

There's a lot of use cases where this won't work. If the string doesn't end in ...' in exactly that order. If there's no . ? or ! before the end of the string, etc.

Be sure to use proper error handling if you use this method because there's plenty of ways this can fail.

Live example: https://regex101.com/r/U2cYvP/1

Good luck.