forked from svrjs/svrjs
70 lines
2.4 KiB
Markdown
70 lines
2.4 KiB
Markdown
# fs-minipass
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Filesystem streams based on [minipass](http://npm.im/minipass).
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4 classes are exported:
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- ReadStream
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- ReadStreamSync
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- WriteStream
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- WriteStreamSync
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When using `ReadStreamSync`, all of the data is made available
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immediately upon consuming the stream. Nothing is buffered in memory
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when the stream is constructed. If the stream is piped to a writer,
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then it will synchronously `read()` and emit data into the writer as
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fast as the writer can consume it. (That is, it will respect
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backpressure.) If you call `stream.read()` then it will read the
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entire file and return the contents.
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When using `WriteStreamSync`, every write is flushed to the file
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synchronously. If your writes all come in a single tick, then it'll
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write it all out in a single tick. It's as synchronous as you are.
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The async versions work much like their node builtin counterparts,
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with the exception of introducing significantly less Stream machinery
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overhead.
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## USAGE
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It's just streams, you pipe them or read() them or write() to them.
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```js
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const fsm = require('fs-minipass')
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const readStream = new fsm.ReadStream('file.txt')
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const writeStream = new fsm.WriteStream('output.txt')
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writeStream.write('some file header or whatever\n')
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readStream.pipe(writeStream)
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```
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## ReadStream(path, options)
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Path string is required, but somewhat irrelevant if an open file
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descriptor is passed in as an option.
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Options:
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- `fd` Pass in a numeric file descriptor, if the file is already open.
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- `readSize` The size of reads to do, defaults to 16MB
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- `size` The size of the file, if known. Prevents zero-byte read()
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call at the end.
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- `autoClose` Set to `false` to prevent the file descriptor from being
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closed when the file is done being read.
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## WriteStream(path, options)
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Path string is required, but somewhat irrelevant if an open file
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descriptor is passed in as an option.
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Options:
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- `fd` Pass in a numeric file descriptor, if the file is already open.
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- `mode` The mode to create the file with. Defaults to `0o666`.
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- `start` The position in the file to start reading. If not
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specified, then the file will start writing at position zero, and be
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truncated by default.
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- `autoClose` Set to `false` to prevent the file descriptor from being
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closed when the stream is ended.
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- `flags` Flags to use when opening the file. Irrelevant if `fd` is
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passed in, since file won't be opened in that case. Defaults to
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`'a'` if a `pos` is specified, or `'w'` otherwise.
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