fs.read(fd, buffer, offset, length, position, callback)

• fd <integer>

• buffer <Buffer> | <TypedArray> | <DataView> 数据将写入的缓冲区。

  ¥buffer <Buffer> | <TypedArray> | <DataView> The buffer that the data will be written to.

• offset <integer> 要写入数据的 buffer 中的位置。

  ¥offset <integer> The position in buffer to write the data to.

• length <integer> 读取的字节数。

  ¥length <integer> The number of bytes to read.

• position <integer> | <bigint> | <null> 指定从文件中开始读取的位置。如果 position 为 null 或 -1 ，则将从当前文件位置读取数据，并更新文件位置。如果 position 是整数，则文件位置将保持不变。

  ¥position <integer> | <bigint> | <null> Specifies where to begin reading from in the file. If position is null or -1 , data will be read from the current file position, and the file position will be updated. If position is an integer, the file position will be unchanged.

• callback <Function>

  • err <Error>

  • bytesRead <integer>

  • buffer <Buffer>

从 fd 指定的文件中读取数据。

¥Read data from the file specified by fd.

回调被赋予三个参数，(err, bytesRead, buffer)。

¥The callback is given the three arguments, (err, bytesRead, buffer).

如果未同时修改文件，当读取的字节数为零时，则到达文件末尾。

¥If the file is not modified concurrently, the end-of-file is reached when the number of bytes read is zero.

如果此方法作为其 util.promisify() 版本被调用，则返回具有 bytesRead 和 buffer 属性的 Object 的 promise。

¥If this method is invoked as its util.promisify()ed version, it returns a promise for an Object with bytesRead and buffer properties.