在JavaScript中将字符串分解为最大字符部分

Question

I need to break apart strings in JavaScript into chunks of no greater than 100 characters while maintaining breaks between words. I have a function in my own personal library for chunkifying a string into 100-character sections, but I can't seem to wrap my head around how to adapt it to avoid splitting in the middle of a word. I figure something can be managed using regular expressions or something, but it just isn't coming to me. One caveat to any solution is that it has to be pure JavaScript, no jQuery, and the environment has no access to browser-related globals.

-- EDIT --

Ok, I've written some code, but I'm getting strange results...

function chunkify(str) {
    var wsRegEx = /\S/;
    var wsEndRegEx = /\s$/;
    var wsStartRegEx = /^\s/;
    var chunks = new Array();
    var startIndex = 0;
    var endIndex = 100;
    var totalChar = 0;
    while (true) {
        if (totalChar >= str.length) break;
        var chunk = str.substr(startIndex,endIndex-startIndex);
        while (wsStartRegEx.test(chunk)) {
            startIndex++;
            endIndex++;
            totalChar++;
            chunk = str.substr(startIndex,endIndex-startIndex);
        }
        if (!wsEndRegEx.test(chunk)) {
            while (wsRegEx.test(chunk.charAt(endIndex))) {
                endIndex--;
            }
            chunk = str.substr(startIndex,endIndex-startIndex);
        }
        chunks.push(chunk);
        totalChar += chunk.length;
        startIndex = endIndex;
        endIndex += 100;
    }
    return chunks;
}

A previous version I posted wasn't counting chunks correctly, but this version, which does seem to break correctly, is now breaking mid word.

-- EDIT #2 --

I think I got it working great now. This seems to do the trick:

function chunkify(str) {
    var wsRegEx = /\S/;
    var chunks = new Array();
    var startIndex = 0;
    var endIndex = 100;
    while (startIndex < str.length) {
        while (wsRegEx.test(str.charAt(endIndex))) {
            endIndex--;
        }
        if (!wsRegEx.test(str.charAt(startIndex)))
            startIndex++;
        chunks.push(str.substr(startIndex, endIndex - startIndex));
        startIndex = endIndex;
        endIndex += 100;
    }
    return chunks;
}

Is there a cleaner way to do this, or have I gotten this to be about as efficient as it'll get?

Answer 1

I have tried to spec this out for you, so you understand one way it can be done

function chunkify (str) {
  var chunks = [];
  var startIdx = 0, endIdx;
  //Traverse through the string, 100 characters at a go
  //If the character in the string after the next 100 (str.charAt(x)) is not a whitespace char, try the previous character(s) until a whitespace character is found.
  //Split on the whitespace character and add it to chunks
  return chunks
}

Answer 2

这是使用正则表达式的一种方法：

chunks = str.match(/.{1,100}/g);