最快的方式扁平化/非扁平化嵌套的JSON对象 [英] Fastest way to flatten / un-flatten nested JSON objects
问题描述
我把一些code一起扁平化和未压扁复杂/嵌套的JSON对象。它的工作原理，但它是一个有点慢（触发'长剧本警告）。
I threw some code together to flatten and un-flatten complex/nested JSON objects. It works, but it's a bit slow (triggers the 'long script' warning).
有关平整名字我想要的。作为分隔符和[索引]数组。
For the flattened names I want "." as the delimiter and [INDEX] for arrays.
例如：
un-flattened | flattened
---------------------------
{foo:{bar:false}} => {"foo.bar":false}
{a:[{b:["c","d"]}]} => {"a[0].b[0]":"c","a[0].b[1]":"d"}
[1,[2,[3,4],5],6] => {"[0]":1,"[1].[0]":2,"[1].[1].[0]":3,"[1].[1].[1]":4,"[1].[2]":5,"[2]":6}
我创建了一个基准，〜摸拟我的使用情况 http://jsfiddle.net/WSzec/
- 获取一个嵌套的JSON对象
- 将其压平
- 在翻阅它，并可能修改它，而扁平化
- Unflatten它回到它原来的嵌套形式被运走
我想更快code：对于澄清，code，它完成的jsfiddle基准（的http：//的jsfiddle .NET / WSzec / ）显著快（〜20％+将是不错）在IE 9 +，24 + FF和Chrome 29 +。
I would like faster code: For clarification, code that completes the JSFiddle benchmark (http://jsfiddle.net/WSzec/) significantly faster (~20%+ would be nice) in IE 9+, FF 24+, and Chrome 29+.
下面是相应的JavaScript code：当前最快： http://jsfiddle.net/WSzec/6/
Here's the relevant JavaScript code: Current Fastest: http://jsfiddle.net/WSzec/6/
JSON.unflatten = function(data) {
"use strict";
if (Object(data) !== data || Array.isArray(data))
return data;
var result = {}, cur, prop, idx, last, temp;
for(var p in data) {
cur = result, prop = "", last = 0;
do {
idx = p.indexOf(".", last);
temp = p.substring(last, idx !== -1 ? idx : undefined);
cur = cur[prop] || (cur[prop] = (!isNaN(parseInt(temp)) ? [] : {}));
prop = temp;
last = idx + 1;
} while(idx >= 0);
cur[prop] = data[p];
}
return result[""];
}
JSON.flatten = function(data) {
var result = {};
function recurse (cur, prop) {
if (Object(cur) !== cur) {
result[prop] = cur;
} else if (Array.isArray(cur)) {
for(var i=0, l=cur.length; i<l; i++)
recurse(cur[i], prop ? prop+"."+i : ""+i);
if (l == 0)
result[prop] = [];
} else {
var isEmpty = true;
for (var p in cur) {
isEmpty = false;
recurse(cur[p], prop ? prop+"."+p : p);
}
if (isEmpty)
result[prop] = {};
}
}
recurse(data, "");
return result;
}
修改1 修改了上面@Bergi的实现，它是目前最快的。顺便说一句，用.indexOf而不是regex.exec为20％左右在FF，但速度慢20％，快于Chrome浏览器;所以我会坚持使用正则表达式，因为它更简单（这里是我尝试使用的indexOf来代替正则表达式 http://jsfiddle.net/WSzec / 2 / ）。
EDIT 1 Modified the above to @Bergi 's implementation which is currently the fastest. As an aside, using ".indexOf" instead of "regex.exec" is around 20% faster in FF but 20% slower in Chrome; so I'll stick with the regex since it's simpler (here's my attempt at using indexOf to replace the regex http://jsfiddle.net/WSzec/2/).
编辑2 大厦@Bergi的想法我要创建一个更快的非正则表达式版本管理（3倍快于FF和〜10％，在Chrome更快）。 http://jsfiddle.net/WSzec/6/ 在此（目前）实现的键名的规则是简单，钥匙无法启动与一个整数或包含句点。
EDIT 2 Building on @Bergi 's idea I managed to created a faster non-regex version (3x faster in FF and ~10% faster in Chrome). http://jsfiddle.net/WSzec/6/ In the this (the current) implementation the rules for key names are simply, keys cannot start with an integer or contain a period.
例如：
- {富：{吧：[0]}} => {foo.bar.0：0}
修改3 添加@AaditMShah的内联路径分析方法（而不是String.split）有助于提高unflatten性能。我很高兴与达到整体性能的提升。
EDIT 3 Adding @AaditMShah 's inline path parsing approach (rather than String.split) helped to improve the unflatten performance. I'm very happy with the overall performance improvement reached.
最新的jsfiddle和jsperf：
The latest jsfiddle and jsperf:
http://jsperf.com/flatten-un-flatten/4
推荐答案
下面是我的短得多的实现：
Here's my much shorter implementation:
JSON.unflatten = function(data) {
"use strict";
if (Object(data) !== data || Array.isArray(data))
return data;
var regex = /\.?([^.\[\]]+)|\[(\d+)\]/g,
resultholder = {};
for (var p in data) {
var cur = resultholder,
prop = "",
m;
while (m = regex.exec(p)) {
cur = cur[prop] || (cur[prop] = (m[2] ? [] : {}));
prop = m[2] || m[1];
}
cur[prop] = data[p];
}
return resultholder[""] || resultholder;
};
JSON.flatten 并没有太大的改变（我不知道你是否真的需要那些的isEmpty 例）：
JSON.flatten hasn't much changed (and I'm not sure whether you really need those isEmpty cases):
JSON.flatten = function(data) {
var result = {};
function recurse (cur, prop) {
if (Object(cur) !== cur) {
result[prop] = cur;
} else if (Array.isArray(cur)) {
for(var i=0, l=cur.length; i<l; i++)
recurse(cur[i], prop + "[" + i + "]");
if (l == 0)
result[prop] = [];
} else {
var isEmpty = true;
for (var p in cur) {
isEmpty = false;
recurse(cur[p], prop ? prop+"."+p : p);
}
if (isEmpty && prop)
result[prop] = {};
}
}
recurse(data, "");
return result;
}
他们一起运行标杆有关时间的一半（歌剧12.16：〜900毫秒，而不是〜1900ms， Chrome浏览器29：〜800毫秒，而不是〜1600ms之间）
Together, they run your benchmark in about the half of the time (Opera 12.16: ~900ms instead of ~ 1900ms, Chrome 29: ~800ms instead of ~1600ms).
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