在字符串中获取最后一个换行符的最有效方法是什么

Question

I have the following function to get the last line break position in a string:

function getLastLineBreak (content) {
    function reverse(s){
        return s.split("").reverse().join("")
    }
    var reversed = reverse(content)
    var index = content.length-reversed.indexOf("\n")
    return index
}

var myString = "some text \n next linet \n another link \n 123"
indexIs = getLastLineBreak(myString)
console.log("index is", indexIs)
console.log("text after", indexIs, myString.substr(indexIs,myString.length))

Is there a way using regular expression to pick up the last line break position within the string in nodejs?

Answer 1

You could use String.prototype.lastIndexOf

 var myString = "some text \\n next linet \\n another link \\n 123"; document.write(myString.lastIndexOf('\\n')); 

Answer 2

This should also work

(.*$)

We can take advantage of the fact that . do not matches new line.

Ideone Demo

JS Code

 var re = /(.*$)/g; var str = 'some text \\n next linet \\n another link \\n 123'; matches = re.exec(str); document.writeln(matches[1]) 

Answer 3

I would do it the old fashioned way. /(\\r?\\n)[^\\r\\n]*$/

This should start from the end of the string and work backwards.
Where the last linebreak is probably closest in most cases.