在JavaScript中将包含多个段落的字符串分成两部分

Question

我有我想分手的字符串文本。我需要通过Facebook信使聊天API发送它，但该API只允许640个字符，而我的文本要长得多。我想要一个整齐的解决方案，我可以通过它发送文本。

我是把包含多个段落的字符串拆分到最近的句号的两半。

如

var str = "This is paragraph one. I need Mr. Sam to my errand. The errand must be done by him. He is the best. 

Mr. Sharma is also good. Btw this is the second paragraph. I think you get my point. Sentence again. Sentence again. 

Paragraph three is started. I am writing so much now. This is fun. Thanks"; 

//Expected output 

var half1 = "This is paragraph one. I need Mr. Sam to my errand. The errand must be done by him. He is the best. 

Mr. Sharma is also good. Btw this is the second paragraph." 

var half2 = "I think you get my point. Sentence again. Sentence again. 

Paragraph three is started. I am writing so much now. This is fun. Thanks" 

Answer 1

var results=[]; 
var start=0; 
for(var i=640;i<str.length;i+=640){//jump to max 
while(str[i]!=="."&&i) i--;//go back to . 
    if(start===i) throw new Error("impossible str!"); 
    results.push(str.substr(start,i-start));//substr to result 
    start=i+1;//set next start 
} 
} 
//add last one 
results.push(str.substr(start)); 

你可以通过使640向前迈出一步，然后回到最后一个走过去的字符串。 ，创建一个子串并重复。

Answer 2

认为这是一个基础：

let slices = [], s; 
for(let i = 0; s = a.slice(i * 640, (i+1) * 640); i++) 
    slices.push(s); 

切片阵列将包含文本字符640块。但我们希望这是空间感知。我们需要在不超过640分的情况下尽可能接近640分。如果我们想知道的空间，它会让我们的生活更容易处理整个句子而不是字符：

// EDIT: Now, if a sentence is less than 640 chars, it will be stored as a whole in sentences 
// Otherwise, it will be stored in sequential 640-char chunks with the last chunk being up to 640 chars and containing the period. 
// This tweak also fixes the periods being stripped 
let sentences = str.match(/([^.]{0,639}\.|[^.]{0,640})/g) 

这里是一个讨厌的正则表达式的行动快速演示：https://jsfiddle.net/w6dh8x7r

现在我们可以一次创建最多640个字符的结果。

let result = '' 
sentences.forEach(sentence=> { 
    if((result + sentence).length <= 640) result += sentence; 
    else { 
     API.send(result); 
     // EDIT: realized sentence would be skipped so changed '' to sentence 
     result = sentence; 
    } 
}) 

Answer 3

var txt = 'This is paragraph one. I need Mr. Sam to my errand. The errand must be done by him. He is the best. Mr. Sharma is also good. Btw this is the second paragraph. I think you get my point. Sentence again. Sentence again. Paragraph three is started. I am writing so much now. This is fun. Thanks' 
    var p = [] 
    splitValue(txt, index); 

    function splitValue(text) 
    { 
     var paragraphlength = 40; 
     if (text.length > paragraphlength) 
     { 
      var newtext = text.substring(0, paragraphlength); 
      p.push(newtext) 
      splitValue(text.substring(paragraphlength + 1, text.length)) 
     } 
    }