我正在寻找一种方法来搜索JSON对象以检查它是否包含给定值，如果它存在，则取消设置。
我的数据结构如下（评论说明）：
// Search within the 'seats' array for a given 'guestID', if it exists, unset it
tables = [
{
"_id":{
$oid: "one"
},
"seats":[
{ "guestId":"01" },
{ "guestId":"02" },
{ "guestId":"03" }
]
},
{
"_id":{
$oid: "two"
},
"seats":[
{ "guestId":"11" },
{ "guestId":"12" },
{ "guestId":"13" }
]
}
]
我在这个项目中使用下划线，我尝试使用_.pluck(tables, 'seats')然后使用_.foreach但是我必须嵌套多个_.foreach语句才能访问座位数组进行搜索，我就是不确定这是不是最好的做法。是否有一种我不知道的简单方法？
此数据是从mongolab REST api返回的。这是我应该在我的初始XHR请求中做的事情，而不是获取一个大对象，然后尝试通过客户端解析它？
如果这是一个SQL请求，我只能做select tables.seats where guestId = XXX
答案 0 :(得分：1)
每当我遇到过去的这种情况时，递归搜索功能总是非常宝贵的...这是我的一个我躺在（我通过添加删除方法扩展它）< / EM>：
function o ( target ) {
/// if an instance of o has been created, then handle it
if ( this instanceof o ) {
/// O INSTANCE:
/// an instance of o acts like a reference or pointer
/// to how the value it targets was reached.
this.value = target;
this.key = arguments[1];
this.parent = arguments[2];
this.toString = function(){ return 'o('+this.key+' = '+this.value+')';}
}
/// if no instance being created fall back to the 'scan object' code
else {
/// RECURSIVE CODE:
/// the _ function is responsible for accepting the
/// attributeName and attributeValue search
var _ = function ( key, value, modifier ) {
var i, v, tar = ( modifier ? modifier.target : target ), items = [];
/// if we are dealing with an o instance, handle slightly differently
if ( tar instanceof o ) {
for ( i in tar.value ) {
/// check to see if our current key and value
/// match our search terms
if ( _.test( i, (v=tar.value[i]), key, value ) ) {
items.push(new o(v, i, tar));
};
};
}
/// if no o instance treat as a normal object or array
else {
for ( i in tar ) {
if ( (v = tar[i]) ) {
/// if we are an instance of o, recurse to actually
/// check the items within
if ( v instanceof o ) {
items = items.concat( _( key, value, {target:v} ) );
}
/// check to see if our current key and value match
/// our search terms
else if ( _.test( i, v, key, value ) ) {
items.push(new o(v, i, tar));
};
};
};
};
/// if in modifier mode, don't rely on storing in scope,
/// return the calculated items instead
if ( modifier ) {
return items;
}
else {
/// update what we are targeting
target = items;
/// return our underscore function
return _;
};
};
/// FUNCTION DECLARATIONS:
/// a quick test to see if the key and value match (or either or)
_.test = function ( i,v,key,value ) {
var havekey = ( key !== null && key !== undefined ),
haveval = ( value !== null && value !== undefined ),
passkey = ( havekey && (i == key || key === '*') ),
passval = ( haveval && (v == value || value === '*') );
return ( havekey && haveval && passkey && passval ) ||
( havekey && !haveval && passkey ) ||
( haveval && !havekey && passval );
};
/// calculate the path needed to reach the object within the structure
_.path = function () {
var i = target.length, paths = [], path, cur, last;
while ( i-- ) {
cur = target[i]; path = [];
do{ last = cur; if ( cur instanceof o ){ path.unshift( cur.key ); } }
while( (cur = cur.parent) );
paths.push(path.join('/'));
};
return ( paths.length == 1 ? paths[0] : paths );
};
/// remove the item we are targeting by stepping back
/// and deleting ourselves from the previous parent
_.remove = function ( removeEntireObject ) {
var i = target.length, paths, path, cur, last;
while ( i-- ) {
cur = target[i];
/// remove the object that has the found attribute
if ( removeEntireObject ) {
if ( cur.parent.parent ) {
cur.parent.parent.value[cur.parent.key] = null;
delete cur.parent.parent.value[cur.parent.key];
}
}
/// otherwise remove only the targeted attribute
else {
cur.parent.value[cur.key] = null;
delete cur.parent.value[cur.key];
}
};
return _;
};
/// a useful function for backwards navigation
_.parent = function () {
var i = target.length, cur, items = [], values = [];
while ( i-- ) {
cur = target[i];
/// remove the object that has the found attribute
if ( cur && cur.parent ) {
/// store the values as we go so we can
/// spot and remove duplicated parents
if ( values.indexOf(cur.parent.value) === -1 ) {
items.push(cur.parent);
values.push(cur.parent.value);
}
}
};
target = items;
return _;
}
/// slimple debugging
_.alert = function () {
var i = target.length, cur;
while ( i-- ) {
cur = target[i];
alert(cur);
};
return _;
};
return _;
};
};
使用示例：
/// remove only the guestId object with a value '01'
o(tables)('*')('seats')('*')('guestId', '01').remove( true );
或：
/// remove the 'guestIds' object in the first slot for either seat
o(tables)('*')('seats')(0)('guestId', '*').parent().remove();
或：
/// remove all 'guestIds' from the first seat
o(tables)(0)('seats')('*')('guestId').parent().remove();
说明：
o(my_object_to_parse)。attributeName搜索。attributeName和attributeValue搜索。*充当简单的通配符，可用于处理基本数组。*可用作attributeName或attributeValue。我暂时没有使用过这段代码，所以它可能不是100％无错误或最佳。然而，它似乎适用于您的特定用例......它还设法处理我在测试时投入的所有内容。使用.remove()，.parent()，.path()和.alert()之外的更多方法进行扩展应该很容易，最好添加一些错误检查。