process.memoryUsage()

• 返回: <Object>
  • rss <integer>
  • heapTotal <integer>
  • heapUsed <integer>
  • external <integer>
  • arrayBuffers <integer>

process.memoryUsage() 方法会返回描述 Node.js 进程的内存使用情况（以字节为单位）的对象。

例如：

console.log(process.memoryUsage());

会返回：

{
  rss: 4935680,
  heapTotal: 1826816,
  heapUsed: 650472,
  external: 49879,
  arrayBuffers: 9386
}

• heapTotal 和 heapUsed 代表 V8 的内存使用情况。
• external 代表 V8 管理的绑定到 Javascript 对象的 C++ 对象的内存使用情况。
• rss，常驻集大小, 是为进程分配的物理内存（总分配内存的子集）的大小，包括所有的 C++ 和 JavaScript 对象与代码。
• arrayBuffers 代表分配给 ArrayBuffer 和 SharedArrayBuffer 的内存，包括所有的 Node.js Buffer。 这也包含在 external 值中。 当 Node.js 被用作嵌入式库时，此值可能为 0，因为在这种情况下可能无法跟踪 ArrayBuffer 的分配。

当使用 Worker 线程时， rss 会是对整个进程都有效的值，而其他字段只代表当前线程。

• Returns: <Object>
  • rss <integer>
  • heapTotal <integer>
  • heapUsed <integer>
  • external <integer>
  • arrayBuffers <integer>

The process.memoryUsage() method returns an object describing the memory usage of the Node.js process measured in bytes.

For example, the code:

console.log(process.memoryUsage());

Will generate:

{
  rss: 4935680,
  heapTotal: 1826816,
  heapUsed: 650472,
  external: 49879,
  arrayBuffers: 9386
}

• heapTotal and heapUsed refer to V8's memory usage.
• external refers to the memory usage of C++ objects bound to JavaScript objects managed by V8.
• rss, Resident Set Size, is the amount of space occupied in the main memory device (that is a subset of the total allocated memory) for the process, including all C++ and JavaScript objects and code.
• arrayBuffers refers to memory allocated for ArrayBuffers and SharedArrayBuffers, including all Node.js Buffers. This is also included in the external value. When Node.js is used as an embedded library, this value may be 0 because allocations for ArrayBuffers may not be tracked in that case.

When using Worker threads, rss will be a value that is valid for the entire process, while the other fields will only refer to the current thread.