版本检查 dart

gistfile1.txt

  String deversion(String version){
    if(version == null || version.compareTo("1.0.0")<0) return version;
    var versions = version.split('.');
    var s = int.parse(versions.first) -1;
    versions[0] = s.toString();
    return versions.join('.');
  }
int versionValue(String version){
   if(version == null) return null;
   var versions = version.split('.'); 
   var v = 0;
   for(var i =0;i < versions.length ;i++){
     v = v *10 + int.parse(versions[i]);
   }
   return v;
}

main(){
  var c = [{"2":3}];
  print('$c is Map? ${c is Map}');
  assert(c.first['type']==null); 
  print('[type]is what? ${c.first["type"] ??"o"}');
  var version = [null,"0.1.1","1.2.3"];
  print('12.1 对比 9.9 ${"12.1".compareTo("9.9")}');
  version.forEach((s)=>print('$s=>${deversion(s)} | ${versionValue(s)}'));
}