Parse through a string to create an array of substrings

Question

I am building a mini search engine on my website that can search for words and has filters.

I need to be able to take a long string, and split it up into an array of smaller substrings. The words (with no filter) should go in one string, and then each filter should go in a separate string. The order of words and filters should not matter.

For example:

If my string is:

"hello before: 01/01/17 after: 01/01/2015"

OR:

"before: 01/01/17 hello after: 01/01/2015"

I would expect my function to return (in any order):

["hello", "before: 01/01/2017", "after: 01/01/2015"]

I figured out how to solve this when the word is before any of the filters, but I'm having trouble splitting up the string if the word is in the middle/end of the string — Shirley Rozenboim
– Shirley Rozenboim, Commented Jan 30, 2017 at 21:16

Nina Scholz · Accepted Answer · 2017-01-30 18:44:30Z

1

You could use whitespace and a positive lookahead for splitting.

console.log("hello before: 01/01/17 after: 01/01/2015".split(/\s*(?=before|after)/));

edited Jan 30, 2017 at 18:44

answered Jan 30, 2017 at 18:39

Nina Scholz

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2 Comments

Shirley Rozenboim Over a year ago

Thanks Nina. Your solution worked great originally, but now I'm trying to solve the problem where the order of words doesn't matter.

Nina Scholz Over a year ago

you could omit the space after : and then split by space and check then the type of the part.

SlugFiller · Accepted Answer · 2017-01-30 21:38:41Z

Are there any specific limitations for code size? I mean, this isn't code-golf or anything, so why not just do it the straight-forward way?

First, you can tokenize this with a simple regular expression

var search_string = "hello before: 01/01/17 after: 01/01/2015";
var regex = /(?:(before|after)\:\s*)?([^ ]*)/g
var token = null;
while ((token = regex.exec(search_string)) != null) {

Then, you can put the arrange them into any data structure you want. For example, we can put the filters into a separate object, as so:

var filters = {};
var words = [];
//...
    if (token[1])
        filters[token[1]] = token[2];
    else
        words.push(token[2]);

After that, you can manipulate these structures any way you want

words.sort();
if (filters['before']) words.push(filters['before']);
if (filters['after']) words.push(filters['after']);
return words;

I'm not sure why you'd want it arranged this way, but this would make things uniform. Alternately, you can use them in a more straightforward way:

var before = Date.parse(filters['before'] || '') || false;
if (before !== false) before = new Date(before);
var after = Date.parse(filters['after'] || '') || false;
if (after !== false) before = new Date(before);
function isDocumentMatchSearch(doc) {
    if (before !== false && doc.date > before) return false;
    if (after !== false && doc.date < after) return false;
    for (var i = 0; i < words.length; i++) {
        if (doc.title.indexOf(words[i]) < 0 &&doc.text.indexOf(words[i]) < 0) return false;
    }
    return true;
}

Since you didn't give a lot of information on what you're searching through, what data types or storage type it's stored in, etc etc, that's the best I can offer.

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