How to word-wrap text to a given row length in characters?

I want to word-wrap text into an array of rows (phrases / lines) with max length of N characters. If a word is bigger than the max row length the word should be cut to the length.

Edit: max length of n characters is never less than 100 chars, I used 10 to show you my code is not working properly

<!-- begin snippet: js hide: false console: true babel: false -->

<!-- language: lang-js -->

const sentence =`Wake has three meanings as a noun, and, yes, just about as many meanings as a verb! So get set. To wake is come out of sleep, a verb you'll recognize from "Wake up! You're asleep at the wheel!" You can wake feelings, as well as the people who are having them. The wake before the funeral caused Mike to wake from his depression and decide to live life to the fullest. His first act was to water ski; he eventually mastered staying upright while crossing the wake of the boat that was towing him.`

// shorten with max characters of 10
console.log(shorten(sentence, 10));

function shorten(str, maxLen) {

  if(str.length <= maxLen) return [str];
  let max, min = 0, i = 1;
  const result = [];
	while (maxLen * i < str.length) {
    max = str.lastIndexOf(' ', maxLen * i);
  	result.push(str.substr(min, max));
    min = max + 1;
    i++;
	}
  return result;
 
}

<!-- end snippet -->

The issue is my code dos't work correctly as you see.

The desired out put would be:

["Wake has", "three", "meanings", "as a noun,", ...]  // each one has length of : 8 - 5 - 8 - 10

You can use regex (?=\S).{0,99}\S(?!\S)|\S{100} in conjunction with .matchAll to find desired blocks of symbols (for parameter equal 100).

Here regex matches:

• (?=\S).{0,99}\S(?!\S) block of one to hundred symbols, that begin and end with non-whitespace symbols, and followed by either whitespace or end of line:
  • (?=\S) lookaround that checks first symbol to be non-whitespace,
  • .{0,99} between 0 and 99 of any symbols, except newlines,
  • \S matches last symbol to be non-whitespace,
  • (?!\S) checks that match is followed by whitespace symbol (to prevent wrapping in the middle of the word)
• \S{100} a hundred of consequent non-whitespace symbols: for cases of very long words, that span over maximum expected line length.

Example of code:
<!-- begin snippet: js hide: false console: true babel: false -->
<!-- language: lang-js -->
const sentence =Wake has three meanings as a noun, and, yes, just about as many meanings as a verb! So get set. To wake is come out of sleep, a verb you'll recognize from "Wake up! You're asleep at the wheel!" You can wake feelings, as well as the people who are having them. The wake before the funeral caused Mike to wake from his depression and decide to live life to the fullest. His first act was to water ski; he eventually mastered staying upright while crossing the wake of the boat that was towing him.

console.log(wrapLines(sentence, 100));

function wrapLines(str, maxLen){
    let reg = new RegExp('(?=\\S).{0,'+(maxLen-1)+'}\\S(?!\\S)|\\S{'+maxLen+'}', 'gm')
    console.log(reg)
    return Array.from(str.matchAll(reg), (m) => m[0]);
}

<!-- end snippet -->

Change it to,

const sentence = `Wake has three meanings as a noun, and, yes, just about as many meanings as a verb! So get set. To wake is come out of sleep, a verb you'll recognize from "Wake up! You're asleep at the wheel!" You can wake feelings, as well as the people who are having them. The wake before the funeral caused Mike to wake from his depression and decide to live life to the fullest. His first act was to water ski; he eventually mastered staying upright while crossing the wake of the boat that was towing him.`;

console.log(shorten(sentence, 10));

function shorten(str, maxLen) {
  if (str.length <= maxLen) return [str];
  
  const result = [];
  let startIndex = 0;
  let endIndex = maxLen;
  
  while (endIndex < str.length) {
    while (str[endIndex] !== ' ' && endIndex > startIndex) {
      endIndex--;
    }
    
    result.push(str.substring(startIndex, endIndex));
    startIndex = endIndex + 1;
    endIndex = startIndex + maxLen;
  }
  
  result.push(str.substring(startIndex));
  
  return result;
}

</details>



# 答案3
**得分**: 1

根据我理解，任务是在等宽字体中对文本进行换行处理。以下是翻译好的部分：

```javascript
// shorten with max characters of 10
console.log(shorten(sentence, 10).map(str => str + ': ' + str.length));

function shorten(str, maxLen) {

    const phrases = [];
    let phrase = '';
    let word = '';

    const addWord = () => {
        if (word) {
            phrase.length + word.length >= maxLen && addPhrase();
            phrase += (phrase ? ' ' : '') + word;
            word = '';
        }
    };

    const addPhrase = () => {
        if (phrase) {
            phrases.push(phrase.length > maxLen ? phrase.substring(0, maxLen) : phrase);
            phrase = '';
        }
    };

    for (let i = 0; i < str.length; i++) {
        const c = str[i];
        c === ' ' ? addWord() : word += c;
    }

    addWord();
    addPhrase();

    return phrases;
}

以上是代码部分的翻译。

const sentence = `Some-long-string-should-be-cut-to-10 Wake has three         meanings as a noun, and, yes, just about as many meanings as a verb! So get set. To wake is come out of sleep, a verb you'll recognize from "Wake up! You're asleep at the wheel!" You can wake feelings, as well as the people who are having them. The wake before the funeral caused Mike to wake from his depression and decide to live life to the fullest. His first act was to water ski; he eventually mastered staying upright while crossing the wake of the boat that was towing him.`

// shorten with max characters of 10
console.log(shorten(sentence, 10).map(str => str + ': ' + str.length));

function shorten(str, maxLen) {

    const phrases = [];
    let phrase = '';
    let word = '';

    const addWord = () => {
        if(word){
            phrase.length + word.length >= maxLen && addPhrase();
            phrase += (phrase ? ' ' : '') + word;
            word = '';
        }
    };

    const addPhrase = () => {
        if(phrase){
            phrases.push(phrase.length > maxLen ? phrase.substring(0, maxLen) : phrase);
            phrase = '';
        }
    };

    for (let i = 0; i < str.length; i++) {
        const c = str[i];
        c === ' ' ? addWord() : word += c;
    }

    addWord();
    addPhrase();

    return phrases;
}

答案4

得分: 1

你可以这样做，如果你没有大量的文本，这可能是可行的：

function textSplitter(text, maxLength){
    var currentPos = 0;
    var result = [];
    while(currentPos < text.length){
        const probe = text.substring(currentPos, currentPos+maxLength); // 取最大长度
        const lastSpace = probe.lastIndexOf(" "); // 回溯到最后一个空格
   
        const item = probe.substring(0, lastSpace); // 取你想要的部分
        result.push(item); // 存储它
        currentPos += item.length + 1; // 1 是空格
    }

    return result;
}

这是未经测试的代码，我预计在某些地方需要+1或-1，但这只是一个示例。
（如果有人想调整并修复它，请随意这样做）。

function textSplitter(text, maxLength){
    var currentPos = 0;
    var result = [];
    while(currentPos < text.length){
        const probe = text.substring(currentPos, currentPos+maxLength); // take max length
        const lastSpace = probe.lastIndexOf(" "); // track back to last space
   
        const item = probe.substring(0, lastSpace); // take what you want
        result.push(item); // store it
        currentPos += item.length + 1; // 1 is the space
    }

    return result;
}