filehandle.write(buffer, offset[, length[, position]])

将 buffer 写入文件。

• buffer <Buffer> | <TypedArray> | <DataView>
• offset <integer> The start position from within buffer where the data to write begins.
• length <integer> The number of bytes from buffer to write. Default: buffer.byteLength - offset
• position <integer> | <null> The offset from the beginning of the file where the data from buffer should be written. If position is not a number, the data will be written at the current position. See the POSIX pwrite(2) documentation for more detail. Default: null
• Returns: <Promise>

Write buffer to the file.

The promise is resolved with an object containing two properties:

• bytesWritten <integer> the number of bytes written
• buffer <Buffer> | <TypedArray> | <DataView> a reference to the buffer written.

It is unsafe to use filehandle.write() multiple times on the same file without waiting for the promise to be resolved (or rejected). For this scenario, use filehandle.createWriteStream().

On Linux, positional writes do not work when the file is opened in append mode. The kernel ignores the position argument and always appends the data to the end of the file.