Util
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trait Util
| package util
Alias for emitter.on(eventName, listener).
Alias for emitter.on(eventName, listener).
emitter.addListener(eventName, listener)
on()
This is used to create a function which conditionally writes to stderr based on the existence of a NODE_DEBUG environment variable.
This is used to create a function which conditionally writes to stderr based on the existence of a NODE_DEBUG environment variable. If the section name appears in that environment variable, then the returned function will be similar to console.error(). If not, then the returned function is a no-op.
util.debuglog(section)
Marks that a method should not be used any more.
Marks that a method should not be used any more.
util.deprecate(function, string)
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.
the event name
the event arguments
emitter.emit(name[, arg1][, arg2][, ...])
Returns a formatted string using the first argument as a printf-like format.
Returns a formatted string using the first argument as a printf-like format.
util.format(format[, ...])
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.
emitter.getMaxListeners()
setMaxListeners()
Inherit the prototype methods from one constructor into another.
Inherit the prototype methods from one constructor into another. The prototype of constructor will be set to a new object created from superConstructor.
As an additional convenience, superConstructor will be accessible through the constructor.super_ property.
util.inherits(constructor, superConstructor)
The util.inspect() method returns a string representation of object that is primarily useful for debugging.
The util.inspect() method returns a string representation of object that is primarily useful for debugging. Additional options may be passed that alter certain aspects of the formatted string.
the given inspect options
util.inspect(object[, options])
Returns the number of listeners listening to the event named eventName.
Returns the number of listeners listening to the event named eventName.
emitter.listenerCount(eventName)
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.
emitter.listeners(eventName)
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.
emitter.on(eventName, listener)
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.
emitter.once(eventName, listener)
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.
emitter.removeAllListeners([eventName])
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.
emitter.removeAllListeners([eventName])
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.
emitter.removeListener(eventName, listener)
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.
emitter.setMaxListeners(n)
The util._extend() method was never intended to be used outside of internal Node.js modules.
The util._extend() method was never intended to be used outside of internal Node.js modules. The community found and used it anyway. It is deprecated and should not be used in new code. JavaScript comes with very similar built-in functionality through Object.assign().
(Since version 6.0.0) Use Object.assign() instead.
util._extend(target, source)
Deprecated predecessor of console.error.
Deprecated predecessor of console.error.
(Since version 4.0.0) Use console.debug() instead.
util.debug(string)
Deprecated predecessor of console.error.
Deprecated predecessor of console.error.
(Since version 4.0.0) Use console.error() instead.
util.error([...])
Returns true if the given "object" is an Array.
Returns true if the given "object" is an Array. Otherwise, returns false.
NOTEInternal alias for Array.isArray.
(Since version 4.0.0) Internal alias for Array.isArray.
util.isArray(object)
Returns true if the given "object" is a Boolean.
Returns true if the given "object" is a Boolean. Otherwise, returns false.
(Since version 4.0.0) Alternative not specified
util.isBoolean(object)
Returns true if the given "object" is a Buffer.
Returns true if the given "object" is a Buffer. Otherwise, returns false.
(Since version 4.0.0) Use Buffer.isBuffer() instead.
util.isBuffer(object)
Returns true if the given "object" is a Date.
Returns true if the given "object" is a Date. Otherwise, returns false.
(Since version 4.0.0) Alternative not specified
util.isDate(object)
Returns true if the given "object" is an Error.
Returns true if the given "object" is an Error. Otherwise, returns false.
(Since version 4.0.0) Alternative not specified
util.isError(object)
Returns true if the given "object" is a Function.
Returns true if the given "object" is a Function. Otherwise, returns false.
(Since version 4.0.0) Alternative not specified
util.isFunction(object)
Returns true if the given "object" is strictly null.
Returns true if the given "object" is strictly null. Otherwise, returns false.
(Since version 4.0.0) Alternative not specified
util.isNull(object)
Returns true if the given "object" is null or undefined.
Returns true if the given "object" is null or undefined. Otherwise, returns false.
(Since version 4.0.0) Alternative not specified
util.isNullOrUndefined(object)
Returns true if the given "object" is a Number.
Returns true if the given "object" is a Number. Otherwise, returns false.
(Since version 4.0.0) Alternative not specified
util.isNumber(object)
Returns true if the given "object" is strictly an Object and not a Function.
Returns true if the given "object" is strictly an Object and not a Function. Otherwise, returns false.
(Since version 4.0.0) Alternative not specified
util.isObject(object)
Returns true if the given "object" is a primitive type.
Returns true if the given "object" is a primitive type. Otherwise, returns false.
(Since version 4.0.0) Alternative not specified
util.isPrimitive(object)
Returns true if the given "object" is a RegExp.
Returns true if the given "object" is a RegExp. Otherwise, returns false.
(Since version 4.0.0) Alternative not specified
util.isRegExp(object)
Returns true if the given "object" is a String.
Returns true if the given "object" is a String. Otherwise, returns false.
(Since version 4.0.0) Alternative not specified
util.isString(object)
Returns true if the given "object" is a Symbol.
Returns true if the given "object" is a Symbol. Otherwise, returns false.
(Since version 4.0.0) Alternative not specified
util.isSymbol(object)
Returns true if the given "object" is undefined.
Returns true if the given "object" is undefined. Otherwise, returns false.
(Since version 4.0.0) Alternative not specified
util.isUndefined(object)
Output with timestamp on stdout.
Output with timestamp on stdout.
(Since version 6.0.0) Use a third party module instead.
util.log(string)
Deprecated predecessor of console.log.
Deprecated predecessor of console.log.
(Since version 0.11.3) Use console.log() instead
util.print([...])
Deprecated predecessor of stream.pipe().
Deprecated predecessor of stream.pipe().
(Since version 4.0.0) Use ReadableStream.pipe(Writable)
util.pump(readableStream, Writable[, callback])
Deprecated predecessor of console.log.
Deprecated predecessor of console.log.
(Since version 0.11.3) Use console.log() instead.
util.puts([...])
Util Singleton