Return a `ReadWrite` stream that flat maps streamed chunks
| Param | Type | Description |
| --- | --- | --- |
| `mapper` | `(chunk: T, encoding: string) => R[]` | Mapper function, mapping each (chunk, encoding) to an array of new chunks (or a promise of such) |
| `options` | `object` | |
| `options.readableObjectMode` | `boolean` | Whether this stream should behave as a readable stream of objects |
| `options.writableObjectMode` | `boolean` | Whether this stream should behave as a writable stream of objects |
## filter(predicate, options)
Return a `ReadWrite` stream that filters out streamed chunks for which the predicate does not hold
| Param | Type | Description |
| --- | --- | --- |
| `predicate` | `(chunk: T, encoding: string) => boolean` | Predicate with which to filter scream chunks |
| `options` | `object` | |
| `options.objectMode` | `boolean` | `boolean` | Whether this stream should behave as a stream of objects |
## reduce(iteratee, initialValue, options)
Return a `ReadWrite` stream that reduces streamed chunks down to a single value and yield that
value
| Param | Type | Description |
| --- | --- | --- |
| `iteratee` | `(chunk: T, encoding: string) => R` | Reducer function to apply on each streamed chunk |
| `initialValue` | `T` | Initial value |
| `options` | `object` | |
| `options.readableObjectMode` | `boolean` | Whether this stream should behave as a readable stream of objects |
| `options.writableObjectMode` | `boolean` | Whether this stream should behave as a writable stream of objects |
## split(separator)
Return a `ReadWrite` stream that splits streamed chunks using the given separator
| Param | Type | Description |
| --- | --- | --- |
| `separator` | `string` | Separator to split by, defaulting to `"\n"` |
## join(separator)
Return a `ReadWrite` stream that joins streamed chunks using the given separator
| Param | Type | Description |
| --- | --- | --- |
| `separator` | `string` | Separator to join with |
## replace(searchValue, replaceValue)
Return a `ReadWrite` stream that replaces occurrences of the given string or regular expression in
the streamed chunks with the specified replacement string
| Param | Type | Description |
| --- | --- | --- |
| `searchValue` | `string | RegExp` | Search string to use |
| `replaceValue` | `string` | Replacement string to use |
## parse()
Return a `ReadWrite` stream that parses the streamed chunks as JSON
## stringify()
Return a `ReadWrite` stream that stringifies the streamed chunks to JSON
## collect(options)
Return a `ReadWrite` stream that collects streamed chunks into an array or buffer
| Param | Type | Description |
| --- | --- | --- |
| `options` | `object` | |
| `options.objectMode` | `boolean` | Whether this stream should behave as a stream of objects |
## concat(streams)
Return a `Readable` stream of readable streams concatenated together
| Param | Type | Description |
| --- | --- | --- |
| `streams` | `...Readable[]` | Readable streams to concatenate |
## merge(streams)
Return a `Readable` stream of readable streams merged together in chunk arrival order
| Param | Type | Description |
| --- | --- | --- |
| `streams` | `...Readable[]` | Readable streams to merge |
## duplex(writable, readable)
Return a `Duplex` stream from a writable stream that is assumed to somehow, when written to,
cause the given readable stream to yield chunks
| Param | Type | Description |
| --- | --- | --- |
| `writable` | `Writable` | Writable stream assumed to cause the readable stream to yield chunks when written to |
| `readable` | `Readable` | Readable stream assumed to yield chunks when the writable stream is written to |
## child(childProcess)
Return a `Duplex` stream from a child process' stdin and stdout
| Param | Type | Description |
| --- | --- | --- |
| childProcess | `ChildProcess` | Child process from which to create duplex stream |
## last(readable)
Return a `Promise` resolving to the last streamed chunk of the given readable stream, after it has
ended
| Param | Type | Description |
| --- | --- | --- |
| `readable` | `Readable` | Readable stream to wait on |
