JS intercepts character length instances in bytes

  • 2020-03-29 23:53:22
  • OfStack


*
  * handle long strings, intercept and add ellipses
  * note: the length of the half Angle is 1, and the length of the whole Angle is 2
  *
  * pStr: string
  * pLen: intercept length
  *
  * return: the truncated string
  *


function autoAddEllipsis(pStr, pLen) { 

    var _ret = cutString(pStr, pLen); 
    var _cutFlag = _ret.cutflag; 
    var _cutStringn = _ret.cutstring; 

    if ("1" == _cutFlag) { 
        return _cutStringn + "..."; 
    } else { 
        return _cutStringn; 
    } 
} 

*
  * gets a string of the specified length
  * note: the length of the half Angle is 1, and the length of the whole Angle is 2
  *
  * pStr: string
  * pLen: intercept length
  *
  * return: the truncated string
  *

function cutString(pStr, pLen) { 

    //Original string length
    var _strLen = pStr.length; 

    var _tmpCode; 

    var _cutString; 

    //By default, the returned string is part of the original string
    var _cutFlag = "1"; 

    var _lenCount = 0; 

    var _ret = false; 

    if (_strLen <= pLen/2) { 
        _cutString = pStr; 
        _ret = true; 
    } 

    if (!_ret) { 
        for (var i = 0; i < _strLen ; i++ ) { 
            if (isFull(pStr.charAt(i))) { 
                _lenCount += 2; 
            } else { 
                _lenCount += 1; 
            } 

            if (_lenCount > pLen) { 
                _cutString = pStr.substring(0, i); 
                _ret = true; 
                break; 
            } else if (_lenCount == pLen) { 
                _cutString = pStr.substring(0, i + 1); 
                _ret = true; 
                break; 
            } 
        } 
    } 

    if (!_ret) { 
        _cutString = pStr; 
        _ret = true; 
    } 

    if (_cutString.length == _strLen) { 
        _cutFlag = "0"; 
    } 

    return {"cutstring":_cutString, "cutflag":_cutFlag}; 
} 

*
  * to determine whether it is a full Angle
  *
  * pChar: a string of length 1
  * return: tbtrue: full Angle
  *                   False: half Angle
  *

 
function isFull (pChar) {
  for (var i = 0; i < pChar.strLen ; i++ ) {     
    if ((pChar.charCodeAt(i) > 128)) { 
        return true; 
    } else { 
        return false; 
    }
}
}

Use cases:

testStr = " test 1 string ";
autoAddEllipsis(testStr, 1); //"Test..."
autoAddEllipsis(testStr, 2); //"Test..."
autoAddEllipsis(testStr, 3); //"Test..."
autoAddEllipsis(testStr, 4); //"Test..."
autoAddEllipsis(testStr, 5); //"The test 1..."
autoAddEllipsis(testStr, 6); //"The test 1..."
autoAddEllipsis(testStr, 7); //"Test 1 word..."


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