post for `structs2 action`

struts2_action.js

/* Structs2的对象序列化
* 
* Example:
*  {a:'a', b:[{c:'c'}, {d:'d'}]}
*  
*  => {'a':'a', 'b[0].c': 'c', 'b[1].d': 'd'}
*
*/
function flattern(o) {
  var result = {};

  function traverse(o, parent) {
    parent = parent || '';
    var k, v, t, i, prefix;

    if (isPrimative(o)) return o;
    if (isObject(o)) {
      prefix = parent ? parent + '.' : '';
      for (k in o) {
        t =  prefix + k;
        v = o[k];
        if (isPrimative(v)) {
          result[t] = v;
        } else {
          traverse(v, t);
        }
      }
    }
    if (isArray(o)) {
      prefix = parent ? parent + '[$]' : '$';
      for (i = 0;i < o.length;i++) {
        t = prefix.replace(/\$/, i);
        v = o[i];
        if (isPrimative(v)) {
          result[t] = v;
        } else {
          traverse(v, t);
        }
      }
    }
  }

  traverse(o);

  return result;
}

function isString(v) {
  return 'string' == typeof v
}

function isBoolean(v) {
  return 'boolean' == typeof v
}

function isNumber(v) {
  return 'number' == typeof v
}

function isArray(v) {
  return '[object Array]' == Object.prototype.toString.call(v)
}

function isObject(v) {
  return '[object Object]' == Object.prototype.toString.call(v)
}

function isEmptyObject(v) {
  if (isObject(v)) {
    var f = false;
    for (var p in v) {
      if (v.hasOwnProperty(p)) {
        f = true;
        break;
      }
    }
    return f;
  }
  return false;
}

function isPrimative(v) {
  return isString(v) || isBoolean(v) || isNumber(v);
}

function flatten(obj) {
  var flattenObj = {};
  walker(obj);
  return flattenObj;

  function walker(value, path) {
    path = path || "" //第一次调用walker, path赋一个空字符串
    if (typeof value === "string" || typeof value === "number" || typeof value === "boolean" || value === null) { //如果发现属性值是原始值, 就把path和属性值放进flattenObj对象里,不再进行递归
      flattenObj[path] = value
    } else { //如果发现属性值是个对象
      for (var i in value) { //就遍历这个对象的所有属性
        var nextPath //计算出传给下次walker调用的path
        if (path === "") { //如果是第一级属性,path就是属性名
          nextPath = i
        } else if (({}).toString.call(value) === "[object Array]") { //如果不是第一级属性,且属性值是数组,则用"path + [属性名]"作为下一级的path
          nextPath = path + "[" + i + "]"
        } else {
          nextPath = path + "." + i //如果不是第一级属性,且属性值是个普通对象,则用 "path + .属性名" 作为下一级的path
        }
        walker(value[i], nextPath) //递归
      }
    }
  }
}

var obj = {
  foo: {
    foo2: {
      foo3: 1,
      foo4: 2
    }
  },
  bar: [1, 2, 3],
  baz: "1"
};

flatten(obj)