filehandle.read([options])
options
<Object>buffer
<Buffer> | <TypedArray> | <DataView> 将填充读取的文件数据的缓冲区。 默认值:Buffer.alloc(16384)
offset
<integer> 缓冲区中开始填充的位置。 默认值:0
length
<integer> 读取的字节数。 默认值:buffer.byteLength - offset
position
<integer> | <null> 从文件开始读取数据的位置。 如果为null
,则将从当前文件位置读取数据,并将更新该位置。 如果position
是整数,则当前文件位置将保持不变。 默认值::null
- 返回: <Promise> 成功时将使用具有以下两个属性的对象履行:
bytesRead
<integer> 读取的字节数buffer
<Buffer> | <TypedArray> | <DataView> 对传入的buffer
参数的引用。
从文件中读取数据,并将其存储在给定的缓冲区中。
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。
options
<Object>buffer
<Buffer> | <TypedArray> | <DataView> A buffer that will be filled with the file data read. Default:Buffer.alloc(16384)
offset
<integer> The location in the buffer at which to start filling. Default:0
length
<integer> The number of bytes to read. Default:buffer.byteLength - offset
position
<integer> | <null> The location where to begin reading data from the file. Ifnull
, data will be read from the current file position, and the position will be updated. Ifposition
is an integer, the current file position will remain unchanged. Default::null
- Returns: <Promise> Fulfills upon success with an object with two properties:
bytesRead
<integer> The number of bytes readbuffer
<Buffer> | <TypedArray> | <DataView> A reference to the passed inbuffer
argument.
Reads data from the file and stores that in the given buffer.
If the file is not modified concurrently, the end-of-file is reached when the number of bytes read is zero.