Why does JavaScript's string.split() not work correctly in certain cases?

Question

I need to split a string of text into its component words, so I'm using a Regex to split it on the empty spaces (in a Typescript file, btw).

splitIntoWords(text: string) : Array<string> {
    const separator = ' ';
    const words = text.split(new RegExp(separator, 'g'));
    return words;
}

This mostly works, but I've noticed that I regularly get words in the array that still contain spaces. If I copy the text into the Chrome console and split(' ') it I get the correct amount of words, but when I use the variable (even in the console) it invariably fails in some cases. I can't work out what the difference is. This is an example of my text:

"Le coronavirus en France : la décrue se poursuit en réanimation, la reprise économique au cœur des préoccupations. La mise en œuvre du plan de déconfinement élaboré par le gouvernement doit encore faire l’objet, jeudi, d’un « travail de concertation et d’adaptation aux réalités de terrain » avec les responsables et les élus locaux."

The regex never manages to split the substring "économique au" into two components, for instance. Does anyone know why this is happening?

I cannot reproduce your problem. Your code works just fine for me. — Jörg W Mittag
– Jörg W Mittag, Commented Apr 30, 2020 at 7:03

Snow · Accepted Answer · 2020-04-29 23:05:06Z

11

It sounds like the whitespace is occasionally not just a plain space. You can split on all whitespace by using \s for the separator instead, which will match any whitespace, including space characters and tab characters.

const text = "Le coronavirus en France : la décrue se poursuit en réanimation, la reprise économique au cœur des préoccupations. La mise en œuvre du plan de déconfinement élaboré par le gouvernement doit encore faire l’objet, jeudi, d’un « travail de concertation et d’adaptation aux réalités de terrain » avec les responsables et les élus locaux.";
const words = text.split(/\s/);
console.log(words);

Another option would be to use match instead of split, and match non-whitespace characters.

const text = "Le coronavirus en France : la décrue se poursuit en réanimation, la reprise économique au cœur des préoccupations. La mise en œuvre du plan de déconfinement élaboré par le gouvernement doit encore faire l’objet, jeudi, d’un « travail de concertation et d’adaptation aux réalités de terrain » avec les responsables et les élus locaux.";
const words = text.match(/\S+/g);
console.log(words);

answered Apr 29, 2020 at 23:05

Snow

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4 Comments

Ralph Lavelle Over a year ago

Thanks - this seems to be the prob. I didn't realise there could be different spaces under different circumstances (variable vs. literal text).

Jörg W Mittag Over a year ago

This doesn't seem to be the problem. The whitespace between économique and au in the OP's question is just a boring old bog-standard U+0020 SPACE 7-bit ASCII character. In fact, I cannot reproduce the OP's problem at all: if I copy&paste the OP's code and the sample text (and I am very careful to preserve all whitespace exactly as it is in the question), then the OP's code works just fine.

Ralph Lavelle Over a year ago

@JörgWMittag It works though. I tried it out. I don't know why there should be a difference between trying this as a literal string ("économique au").split(), and using a variable (text.split()), but there is.

SalahAdDin Over a year ago

I tried everything till I found this solution, both two worked pretty well.

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