javascript中不同数据类型的内存使用情况 [英] Memory Usage Of Different Data Types in javascript

问题描述

我遇到的一个问题是，javascript中的不同数据类型有多少使用内存。例如，在C ++数据类型中，如int，char，float使用2,1,8字节的内存顺序。现在数据类型像数字，字符串，布尔值，空，undefind和对象，javascript中的数组使用多少内存以及接受的范围是多少？
因为我的英语水平低而接受我的道歉!!!

A question that has happened to me is that different Data type in javascript how many use of memory . for Example in C++ data type like int , char , float uses order 2 , 1 , 8 byte of memory . now data Type like Number , string , boolean , null , undefind and Objects , Arrays in javascript how many use of memory and what is ranges that accepted ? Accept my apologize because of my low English level!!!

推荐答案

数字是8个字节。

在 w3schools页面中找到。

我为其他JavaScript基元类型搜索了一下，但是很难找到这些信息！我确实找到了以下代码：

I searched around a bit more for other JavaScript primitive types, but it's surprisingly hard to find this information! I did find the following code though:

    ...
    if ( typeof value === 'boolean' ) {
        bytes += 4;
    }
    else if ( typeof value === 'string' ) {
        bytes += value.length * 2;
    }
    else if ( typeof value === 'number' ) {
        bytes += 8;
    }
    ...

似乎表示字符串是2个字节每个字符，布尔值是4个字节。

Seems to indicate that a String is 2 bytes per character, and a boolean is 4 bytes.

发现代码此处和此处。完整代码实际上用于获取对象的粗略大小。

Found that code here and here. The full code's actually used to get the rough size of an object.

虽然在进一步阅读后，我发现了这个有趣的代码konijn ：计算字符串的字节长度。

Although, upon further reading, I found this interesting code by konijn on this page: Count byte length of string.

function getByteCount( s )
{
  var count = 0, stringLength = s.length, i;
  s = String( s || "" );
  for( i = 0 ; i < stringLength ; i++ )
  {
    var partCount = encodeURI( s[i] ).split("%").length;
    count += partCount==1?1:partCount-1;
  }
  return count;
}
getByteCount("i♥js"); // 6 bytes
getByteCount("abcd"); // 4 bytes

因此，内存中字符串的大小似乎取决于字符本身。虽然我仍在试图找出为什么他将数量设置为1，如果它是1，否则他拿了 count-1 （在for循环中）。

So it seems that the string's size in memory depends on the characters themselves. Although I am still trying to figure out why he set the count to 1 if it's 1, otherwise he took count-1 (in the for loop).

如果我发现其他任何内容，我会更新帖子。

Will update post if I find anything else.

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