VI-I: re

Friday, February 6, 2009

[Rel] JavaScript正则表达式生成器

看到某写的东西，找不到留言的地方，遂自己写一个。


//原始实现
function convertToJsEsc(chars) {
    var result = '';

    for(var i=0; i<chars.length; i++) {
        var code = chars.charCodeAt(i);
        switch (code) {
            case 0x20: result += "\\s";     break;
            case 0x22: result += "\\\"";    break;
            case 0x27: result += "\\\'";    break;
            case 0x28: result += "\\(";     break;
            case 0x29: result += "\\)";     break;
            case 0x2A: result += "\\*";     break;
            case 0x2B: result += "\\+";     break;
            case 0x2E: result += "\\.";     break;
            case 0x2F: result += "\\/";     break;
            case 0x3F: result += "\\?";     break;
            case 0x5B: result += "\\[";     break;
            case 0x5C: result += "\\\\";    break;
            case 0x5D: result += "\\]";     break;
            case 0x7B: result += "\\{";     break;
            case 0x7D: result += "\\}";     break;
            default:
                if(code > 0x1F && code < 0x7F) { result += chars[i]; }
                else { result += "\\u" + code.toString(16).toUpperCase(); }
                break;
        }
    }
    return result === "" ? "Nothing to convert" : result;
}

//我的修改
function convertToJsEsc(chars) {
    return chars && chars.replace(
        /([ "'\(\)\*\+\.\/\?\[\\\]\{\}])|([\x1F-\x7F])|(.)/g,
        function(all, a, b, c){
          return a ? 
              ('\\' + (all==' '?'s':all)) :
              b ? 
              all :
              ('\\u' + all.charCodeAt().toString(16).toUpperCase());
        }
      ) || 'Nothing to convert';
}

有啥区别？
优点：方便修改
缺点：难于理解。