JavaScript 对象中的深度变化值

Question

我有一个对象，其中包含未知数量的其他对象。每个（子）对象都可能包含字符串形式的布尔值，我想将它们更改为真正的布尔值。这是一个示例对象：

var myObj = {
  my1stLevelKey1: "true",
  my1stLevelKey2: "a normal string",
  my1stLevelKey3: {
    my2ndLevelKey1: {
      my3rdLevelKey1: {
        my4thLevelKey1: "true",
        my4thLevelKey2: "false"
      }
    },
    my2ndLevelKey2: {
      my3rdLevelKey2: "FALSE"
    }
  }
}

我最终想要的是这样的：

var myObj = {
  my1stLevelKey1: true,
  my1stLevelKey2: "a normal string",
  my1stLevelKey3: {
    my2ndLevelKey1: {
      my3rdLevelKey1: {
        my4thLevelKey1: true,
        my4thLevelKey2: false
      }
    },
    my2ndLevelKey2: {
      my3rdLevelKey2: false
    }
  }
}

重要的是 sub-objects/levels 这个数字是未知的。如何使用经典 JavaScript 或 Mootools 有效地做到这一点？

Answer 1

递归是你的朋友

(function (obj) { // IIFE so you don't pollute your namespace
    // define things you can share to save memory
    var map = Object.create(null);
    map['true'] = true;
    map['false'] = false;
    // the recursive iterator
    function walker(obj) {
        var k,
            has = Object.prototype.hasOwnProperty.bind(obj);
        for (k in obj) if (has(k)) {
            switch (typeof obj[k]) {
                case 'object':
                    walker(obj[k]); break;
                case 'string':
                    if (obj[k].toLowerCase() in map) obj[k] = map[obj[k].toLowerCase()]
            }
        }
    }
    // set it running
    walker(obj);
}(myObj));

obj[k].toLowerCase()是为了不区分大小写

Answer 2

遍历对象的每个级别并将布尔字符串值替换为适当的布尔值。如果找到一个对象，递归并再次替换。

您可以使用 Object.keys 获取每个对象的所有成员，而不用担心获得您不应该继承的属性。

var myObj = {
  my1stLevelKey1: "true",
  my1stLevelKey2: "a normal string",
  my1stLevelKey3: {
    my2ndLevelKey1: {
      my3rdLevelKey1: {
        my4thLevelKey1: "true",
        my4thLevelKey2: "false"
      }
    },
    my2ndLevelKey2: {
      my3rdLevelKey2: "FALSE"
    }
  }
};

function booleanizeObject(obj) {
  var keys = Object.keys(obj);
  keys.forEach(function(key) {
    var value = obj[key];
    if (typeof value === 'string') {
      var lvalue = value.toLowerCase();
      if (lvalue === 'true') {
        obj[key] = true;
      } else if (lvalue === 'false') {
        obj[key] = false;
      }
    } else if (typeof value === 'object') {
      booleanizeObject(obj[key]);
    }
  });
}

booleanizeObject(myObj);

document.getElementById('results').textContent = JSON.stringify(myObj);

<pre id="results"></pre>

Answer 3

JavaScript 数据结构可以通过递归函数 reduce 方法优雅地清理。

var myObj = {
  my1stLevelKey1: "true",
  my1stLevelKey2: "a normal string",
  my1stLevelKey3: {
    my2ndLevelKey1: {
      my3rdLevelKey1: {
        my4thLevelKey1: "true",
        my4thLevelKey2: "false"
      }
    },
    my2ndLevelKey2: {
      my3rdLevelKey2: "FALSE"
    }
  }
};


myObj = Object.keys(myObj).reduce(function sanitizeBooleanStructureRecursively (collector, key) {
  var
    source  = collector.source,
    target  = collector.target,

    value   = source[key],

    str
  ;
  if (value && (typeof value == "object")) {

    value = Object.keys(value).reduce(sanitizeBooleanStructureRecursively, {

      source: value,
      target: {}

    }).target;

  } else if (typeof value == "string") {

    str   = value.toLowerCase();
    value = ((str == "true") && true) || ((str == "false") ? false : value)
  }
  target[key] = value;

  return collector;

}, {

  source: myObj,
  target: {}

}).target;


console.log(myObj);

Answer 4

普通javascript递归示例：

function mapDeep( obj ) {
    for ( var prop in obj ) {
        if ( obj[prop] === Object(obj[prop]) ) mapDeep( obj[prop] );
        else if ( obj[prop].toLowerCase() === 'false' ) obj[prop] = false;
        else if ( obj[prop].toLowerCase() === 'true' ) obj[prop] = true;
    }                   
};

和 MooTools 示例，通过使用自定义 mapDeep() 函数扩展 Object 类型：

Object.extend( 'mapDeep', function( obj, custom ) {
    return Object.map( obj, function( value, key ) {
        if ( value === Object( value ) )
            return Object.mapDeep( value, custom );
        else
            return custom( value, key );                    
    });
});


myObj = Object.mapDeep( myObj, function( value, key ) {
    var bool = { 'true': true, 'false': false };        
    return value.toLowerCase() in bool ? bool[ value.toLowerCase() ] : value;           
})

JavaScript 对象中的深度变化值

Deep changing values in a JavaScript object

javascript

recursion

mootools

functional-programming

data-structures