Javascript 从字符串中获取字符串的startoffset和endoffset

我不熟悉

angularjs

和

webdevelopment

。在这里，我有一个字符串，它是所选的字符串，类似于-

var getSelectedText=function（）{
var text=“”；
if（typeof window.getSelection！=“未定义”）{
text=window.getSelection（）.toString（）；
}else if（type of document.selection！=“未定义”&&document.selection.type==“文本”）{
text=document.selection.createRange（）.text；
}
$scope.annotations=annotationList（）；
返回文本；
};尝试一下并查看评论：

var str = 'a string to search for a value within, we can add as many words as we want here';

function findWithin(str, searchTerm){
  var index = str.indexOf(searchTerm);
  if(index !== -1){
    // at this point we know the string is within the text
    // the start offset will be the place we found the searchTerm
    // the end offset will be the length of the whole str minus the length from the start of the str to the end of the searchTerm

    var endOfSearchTerm = index + searchTerm.length;
    var endOffset = str.length - endOfSearchTerm;
    return { startOffset: index, endOffset:  endOffset}
  } else {
     return 'string not found in text!'
  }
}

findWithin(str, 'we can add as many')