trait ChildProcess extends Object with IEventEmitter
The child_process module provides the ability to spawn child processes in a manner that is similar, but not identical, to popen(3). This capability is primarily provided by the child_process.spawn() function.
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- @RawJSType() @native()
- See also
https://nodejs.org/api/child_process.html
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!=(arg0: Any): Boolean
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def
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def
addListener(eventName: String, listener: Function): ChildProcess.this.type
Alias for emitter.on(eventName, listener).
Alias for emitter.on(eventName, listener).
- Definition Classes
- IEventEmitter
emitter.addListener(eventName, listener)
- See also
on()
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final
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domain: String
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def
emit(name: String, args: Any*): Any
Synchronously calls each of the listeners registered for the event named eventName, in the order they were registered, passing the supplied arguments to each.
Synchronously calls each of the listeners registered for the event named eventName, in the order they were registered, passing the supplied arguments to each.
Returns true if the event had listeners, false otherwise.
- name
the event name
- args
the event arguments
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- IEventEmitter
emitter.emit(name[, arg1][, arg2][, ...])
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eq(arg0: AnyRef): Boolean
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def
exec(command: String, options: |[ExecOptions, RawOptions], callback: Function3[Error, |[Buffer, String], |[Buffer, String], Any]): ChildProcess.this.type
Spawns a shell then executes the command within that shell, buffering any generated output.
Spawns a shell then executes the command within that shell, buffering any generated output.
- command
<String> The command to run, with space-separated arguments
- options
the execution options
- callback
called with the output when process terminates
- returns
the ChildProcess
child_process.exec(command[, options][, callback])
Example: -
def
exec(command: String, callback: Function3[Error, |[Buffer, String], |[Buffer, String], Any]): ChildProcess.this.type
Spawns a shell then executes the command within that shell, buffering any generated output.
Spawns a shell then executes the command within that shell, buffering any generated output.
- command
<String> The command to run, with space-separated arguments
- callback
called with the output when process terminates
- returns
the ChildProcess
child_process.exec(command[, options][, callback])
Example: -
def
exec(command: String, options: |[ExecOptions, RawOptions]): ChildProcess.this.type
Spawns a shell then executes the command within that shell, buffering any generated output.
Spawns a shell then executes the command within that shell, buffering any generated output.
- command
<String> The command to run, with space-separated arguments
- options
the execution options
- returns
the ChildProcess
child_process.exec(command[, options][, callback])
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def
finalize(): Unit
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def
fork(modulePath: String, args: Array[String] = js.native, options: |[ForkOptions, RawOptions] = js.native): ChildProcess.this.type
The child_process.fork() method is a special case of child_process.spawn() used specifically to spawn new Node.js processes.
The child_process.fork() method is a special case of child_process.spawn() used specifically to spawn new Node.js processes. Like child_process.spawn(), a ChildProcess object is returned. The returned ChildProcess will have an additional communication channel built-in that allows messages to be passed back and forth between the parent and child. See child.send() for details.
It is important to keep in mind that spawned Node.js child processes are independent of the parent with exception of the IPC communication channel that is established between the two. Each process has its own memory, with their own V8 instances. Because of the additional resource allocations required, spawning a large number of child Node.js processes is not recommended.
By default, child_process.fork() will spawn new Node.js instances using the process.execPath of the parent process. The execPath property in the options object allows for an alternative execution path to be used.
Node.js processes launched with a custom execPath will communicate with the parent process using the file descriptor (fd) identified using the environment variable NODE_CHANNEL_FD on the child process. The input and output on this fd is expected to be line delimited JSON objects.
Note: Unlike the fork(2) POSIX system call, child_process.fork() does not clone the current process.
- modulePath
<String> The module to run in the child
- args
<Array> List of string arguments
- options
the fork options
- returns
the ChildProcess
child_process.fork(modulePath[, args][, options])
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final
def
getClass(): Class[_]
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def
getMaxListeners(): Int
Returns the current max listener value for the EventEmitter which is either set by emitter.setMaxListeners(n) or defaults to EventEmitter.defaultMaxListeners.
Returns the current max listener value for the EventEmitter which is either set by emitter.setMaxListeners(n) or defaults to EventEmitter.defaultMaxListeners.
- Definition Classes
- IEventEmitter
emitter.getMaxListeners()
- See also
setMaxListeners()
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def
hasOwnProperty(v: String): Boolean
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def
hashCode(): Int
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final
def
isInstanceOf[T0]: Boolean
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def
isPrototypeOf(v: Object): Boolean
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def
listenerCount(eventName: String): Int
Returns the number of listeners listening to the event named eventName.
Returns the number of listeners listening to the event named eventName.
- Definition Classes
- IEventEmitter
emitter.listenerCount(eventName)
Example: -
def
listeners(eventName: String): Array[Function]
Returns a copy of the array of listeners for the event named eventName.
Returns a copy of the array of listeners for the event named eventName.
- Definition Classes
- IEventEmitter
emitter.listeners(eventName)
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final
def
ne(arg0: AnyRef): Boolean
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final
def
notify(): Unit
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final
def
notifyAll(): Unit
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def
on(eventName: String, listener: Function): ChildProcess.this.type
Adds the listener function to the end of the listeners array for the event named eventName.
Adds the listener function to the end of the listeners array for the event named eventName. No checks are made to see if the listener has already been added. Multiple calls passing the same combination of eventName and listener will result in the listener being added, and called, multiple times.
Returns a reference to the EventEmitter so calls can be chained.
- Definition Classes
- IEventEmitter
emitter.on(eventName, listener)
Example: -
def
once(eventName: String, listener: Function): ChildProcess.this.type
Adds a one time listener function for the event named eventName.
Adds a one time listener function for the event named eventName. This listener is invoked only the next time eventName is triggered, after which it is removed.
- Definition Classes
- IEventEmitter
emitter.once(eventName, listener)
Example: -
def
propertyIsEnumerable(v: String): Boolean
- Definition Classes
- Object
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def
removeAllListeners(): ChildProcess.this.type
Removes all listeners, or those of the specified eventName.
Removes all listeners, or those of the specified eventName.
Note that it is bad practice to remove listeners added elsewhere in the code, particularly when the EventEmitter instance was created by some other component or module (e.g. sockets or file streams).
Returns a reference to the EventEmitter so calls can be chained.
- Definition Classes
- IEventEmitter
emitter.removeAllListeners([eventName])
Example: -
def
removeAllListeners(eventName: String): ChildProcess.this.type
Removes all listeners, or those of the specified eventName.
Removes all listeners, or those of the specified eventName.
Note that it is bad practice to remove listeners added elsewhere in the code, particularly when the EventEmitter instance was created by some other component or module (e.g. sockets or file streams).
Returns a reference to the EventEmitter so calls can be chained.
- Definition Classes
- IEventEmitter
emitter.removeAllListeners([eventName])
Example: -
def
removeListener(eventName: String, listener: Function): ChildProcess.this.type
Removes the specified listener from the listener array for the event named eventName.
Removes the specified listener from the listener array for the event named eventName. removeListener will remove, at most, one instance of a listener from the listener array. If any single listener has been added multiple times to the listener array for the specified eventName, then removeListener must be called multiple times to remove each instance.
Note that once an event has been emitted, all listeners attached to it at the time of emitting will be called in order. This implies that any removeListener() or removeAllListeners() calls after emitting and before the last listener finishes execution will not remove them from emit() in progress. Subsequent events will behave as expected.
- Definition Classes
- IEventEmitter
emitter.removeListener(eventName, listener)
Example: -
def
setMaxListeners(n: Int): ChildProcess.this.type
By default EventEmitters will print a warning if more than 10 listeners are added for a particular event.
By default EventEmitters will print a warning if more than 10 listeners are added for a particular event. This is a useful default that helps finding memory leaks. Obviously, not all events should be limited to just 10 listeners. The emitter.setMaxListeners() method allows the limit to be modified for this specific EventEmitter instance. The value can be set to Infinity (or 0) for to indicate an unlimited number of listeners.
Returns a reference to the EventEmitter so calls can be chained.
- Definition Classes
- IEventEmitter
emitter.setMaxListeners(n)
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def
spawn(command: String, args: Array[String] = js.native, options: |[SpawnOptions, RawOptions] = js.native): ChildProcess.this.type
The child_process.spawn() method spawns a new process using the given command, with command line arguments in args.
The child_process.spawn() method spawns a new process using the given command, with command line arguments in args. If omitted, args defaults to an empty array.
- command
<String> The command to run
- args
<Array> List of string arguments
- options
the spawn options
- returns
the ChildProcess
child_process.spawn(command[, args][, options])
Example: -
final
def
synchronized[T0](arg0: ⇒ T0): T0
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def
toLocaleString(): String
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def
toString(): String
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val
usingDomains: Boolean
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def
valueOf(): Any
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final
def
wait(): Unit
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final
def
wait(arg0: Long, arg1: Int): Unit
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final
def
wait(arg0: Long): Unit
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