我有一个由“br”和“nbsp;”组成的字符串标签，我需要的是，我需要将字符限制为100，这意味着只应显示100个字符，因为每个“br”需要4个字符而不是100我得到108，要获得低于输出我可以在单行
data.substr(0,100)
output =＆gt;
制作一本样本书。
它不仅存在了五个世纪，而且还存在了飞跃
但它包含br标签我不想删除br和nbsp;但不要指望
预期输出=＆gt;
制作一本样本书。
它不仅存在了五个世纪，而且还存在于跳跃中。
我已经完成了一些代码片段，但它的计数为108
var data = `it to make a type specimen book. <br><br>It has survived not only five centuries, but also the leap into electronic typesetting, <br><br>remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages<br><br>, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.`
// removes nbsp
var docDesc = data.replace(/[&]nbsp[;]/gi," ");
// removes br
var stringData = docDesc.replace(/[<]br[^>]*[>]/gi,"");
var subData = stringData.substr(0,100)
function test(subData) {
var n = subData.split(" ");
return n.slice(Math.max(n.length - 5, 1))
}
var lastData = test(subData);
var lastString = lastData.join(" ")
var finalData = data.substring(0,data.indexOf(lastString)) + lastString
console.log(finalData)
console.log(finalData.length)
答案 0 :(得分：1)
在它最简单的形式中，您可以编写一个像子字符串一样的函数，但不包括某些单词＆＃39;，就像这样：
function substringWithExcludes(str, excludes, length) {
let idx = 0;
let len = 0;
while(idx < str.length && len < length){
let match = false;
for(let exclude of excludes) {
if(str.startsWith(exclude, idx)) {
idx += exclude.length;
match = true;
break;
}
}
if(!match) {
len++;
idx++;
}
}
return str.substring(0, idx);
}
这叫做：
const data = `it to make a type specimen book. <br>\r\n<br>\r\nIt has survived not only five centuries, but also the leap into electronic typesetting, <br>\r\n<br>\r\nremaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages<br>\r\n<br>\r\n, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.`;
const result = substringWithExcludes(data, ["\r", "\n", " ", "<br>"], 100);
len会在没有<br>的情况下跟踪字符串的长度以及所有这些，而idx包含这些匹配。我们需要为每个排除做的是，首先查看它是否匹配，以及它是否确实将长度添加到idx。如果它不匹配需要包含的有效字符（增加len和idx）。
对于大型length和许多excludes，可能会很慢，但它可以完成工作。您可以为不区分大小写添加特定案例，并在必要时进行<br />匹配。可以在需要时使用正则表达式匹配来交换startsWith。
答案 1 :(得分：0)
@DILEEP ，请查看以下代码。
如果您在理解代码时遇到任何问题，也请发表评论，我会尽力回答您。
/*
Function takes a string (data)
Returns string with first 100 characters from index 0 to 100 (default)
Returns string based on explicity passed values of start and end
*/
function get100charsNoCountBrsAndSpaces(data, start=0, end=100) {
var arr = stringToArrWithNoBrsAndSpaces(data)
let arrSpaces = arr.map((item) => {
return item.join(' ')
})
let strBrsSpaces = arrSpaces.join(' '); // "sdd fhhf fhhhf fhhf"
var finalStr;
var spacesCount = 0;
//
do {
finalStr = strBrsSpaces.slice(start, end + spacesCount)
spacesCount = finalStr.match(/\s/gi).length
}
while(finalStr.slice(start, end + spacesCount).split(' ').join('').length < 100);
return finalStr.slice(start, end + spacesCount)
}
/*
Function that removes <br> and spaces from string (data)
and returns a 2d array (it helps us in recontruction of original string)
*/
function stringToArrWithNoBrsAndSpaces(data) {
var arrNoBrs = data.split('<br>')
// console.log(JSON.stringify(arrNoBrs, null, 4))
let arrNoBrsSpaces = arrNoBrs.map((item) => {
let a = []; //let: local scope of a
a = item.split(' ')
return a;
})
// console.log(JSON.stringify(arrNoBrsSpaces, null, 4))
return arrNoBrsSpaces
}
/*
Function which reconstructs the string from the 2 array
Adds spaces and <br> at proper places
*/
function arrWithNoBrsAndSpacesToString(array) {
let arrSpaces = array.map((item) => {
return item.join(' ')
})
console.log(arrSpaces)
// console.log(arrSpaces)
let strBrsSpaces = arrSpaces.join('<br>')
return strBrsSpaces
}
// ********* Testing: stringToArrsWithNoBrsAndSpaces()
var inputStr = `it to make a type specimen book. <br><br>It has survived not only five centuries, but also the leap into electronic typesetting, <br><br>remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages<br><br>, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.`
var arr = stringToArrWithNoBrsAndSpaces(inputStr)
console.log(arr)
console.log('\n')
// ********* Testing: arrWithNoBrsAndSpacesToString()
var str = arrWithNoBrsAndSpacesToString(arr)
console.log(str)
// ********* Testing: get100charsNoCountBrsAndSpaces(inputStr)
var finalData = get100charsNoCountBrsAndSpaces(inputStr)
console.log('finalData:', finalData)
console.log('Length:', finalData.length) // 122 (100 char + 22 spaces), see below line
console.log('Number of spaces:', finalData.match(/\s/ig).length)
console.log('Number of chars :', finalData.split(' ').join('').length) // 100
/* ...** Output: stringToArrsWithNoBrsAndSpaces(inputStr) **...
[
[
"it",
"to",
"make",
"a",
"type",
"specimen",
"book.",
""
],
[
""
],
[
"It",
"has",
"survived",
"not",
"only",
"five",
"centuries,",
"but",
"also",
"the",
"leap",
"into",
"electronic",
"typesetting,",
""
],
[
""
],
[
"remaining",
"essentially",
"unchanged.",
"It",
"was",
"popularised",
"in",
"the",
"1960s",
"with",
"the",
"release",
"of",
"Letraset",
"sheets",
"containing",
"Lorem",
"Ipsum",
"passages"
],
[
""
],
[
",",
"and",
"more",
"recently",
"with",
"desktop",
"publishing",
"software",
"like",
"Aldus",
"PageMaker",
"including ",
"versions",
"of",
"Lorem",
"Ipsum."
]
]
*/
/* ...** Output: arrWithNoBrsAndSpacesToString(arr) **...
it to make a type specimen book. <br><br>It has survived not only five centuries, but also the leap into electronic typesetting, <br><br>remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages<br><br>, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.
*/
/* ...** Output: get100charsNoCountBrsAndSpaces(inputStr) **...
it to make a type specimen book. <br><br>It has survived not only five centuries, but also the leap into electronic typesetting, <br><br>remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages<br><br>, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.
finalData: it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting,
Length: 122
Number of spaces: 22
Number of chars : 100
*/
感谢。