ObjectFSWatcher

file system watch object

When the call fs.watch(target)is successful, an object of this type is returned

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
var fs = require("fs");
var watcher = fs.watch((eventType, filename) => {
    if (filename) {
        console.log(filename);
        // Prints: <Buffer ...>
    }
});

watcher.close();

// calling fs.watch with callback and options
fs.watch('./tmp', {
    encoding: 'buffer'
}, (eventType, filename) => {
    if (filename) {
        console.log(filename);
        // Prints: <Buffer ...>
    }
});

inheritance relationship

static properties

defaultMaxListeners

Integer, the default global maximum number of listeners

1
static Integer FSWatcher.defaultMaxListeners;

member properties

onchange

Function, query and bind the "file change" event, equivalent to on("change", func);

1
Function FSWatcher.onchange;

---

onclose

Function, query and bind the "watcher close" event, equivalent to on("close", func);

1
Function FSWatcher.onclose;

---

onerror

Function, query and bind the event of "error occurrence", equivalent to on("error", func);

1
Function FSWatcher.onerror;

member function

close

Close the Watcher and no longer receive corresponding file change processing events.

1
FSWatcher.close();

---

on

Bind an event handler to the object

1
2
Object FSWatcher.on(String ev,
    Function func);

Call parameters:

• ev: String, specifies the name of the event
• func: Function, specify the event processing function

Return results:

• Object, returns the event object itself to facilitate chain calls

---

Bind an event handler to the object

1
Object FSWatcher.on(Object map);

Call parameters:

• map: Object, specifies the event mapping relationship, the object attribute name will be used as the event name, and the value of the attribute will be used as the event processing function

Return results:

• Object, returns the event object itself to facilitate chain calls

---

addListener

Bind an event handler to the object

1
2
Object FSWatcher.addListener(String ev,
    Function func);

Call parameters:

• ev: String, specifies the name of the event
• func: Function, specify the event processing function

Return results:

• Object, returns the event object itself to facilitate chain calls

---

Bind an event handler to the object

1
Object FSWatcher.addListener(Object map);

Call parameters:

• map: Object, specifies the event mapping relationship, the object attribute name will be used as the event name, and the value of the attribute will be used as the event processing function

Return results:

• Object, returns the event object itself to facilitate chain calls

---

prependListener

Bind an event handler to the object's origin

1
2
Object FSWatcher.prependListener(String ev,
    Function func);

Call parameters:

• ev: String, specifies the name of the event
• func: Function, specify the event processing function

Return results:

• Object, returns the event object itself to facilitate chain calls

---

Bind an event handler to the object's origin

1
Object FSWatcher.prependListener(Object map);

Call parameters:

• map: Object, specifies the event mapping relationship, the object attribute name will be used as the event name, and the value of the attribute will be used as the event processing function

Return results:

• Object, returns the event object itself to facilitate chain calls

---

once

Bind a one-time event handler to the object. The one-time handler will only be triggered once.

1
2
Object FSWatcher.once(String ev,
    Function func);

Call parameters:

• ev: String, specifies the name of the event
• func: Function, specify the event processing function

Return results:

• Object, returns the event object itself to facilitate chain calls

---

Bind a one-time event handler to the object. The one-time handler will only be triggered once.

1
Object FSWatcher.once(Object map);

Call parameters:

• map: Object, specifies the event mapping relationship, the object attribute name will be used as the event name, and the value of the attribute will be used as the event processing function

Return results:

• Object, returns the event object itself to facilitate chain calls

---

prependOnceListener

Bind an event handler to the object's origin

1
2
Object FSWatcher.prependOnceListener(String ev,
    Function func);

Call parameters:

• ev: String, specifies the name of the event
• func: Function, specify the event processing function

Return results:

• Object, returns the event object itself to facilitate chain calls

---

Bind an event handler to the object's origin

1
Object FSWatcher.prependOnceListener(Object map);

Call parameters:

• map: Object, specifies the event mapping relationship, the object attribute name will be used as the event name, and the value of the attribute will be used as the event processing function

Return results:

• Object, returns the event object itself to facilitate chain calls

---

off

Unassign a function from the object processing queue

1
2
Object FSWatcher.off(String ev,
    Function func);

Call parameters:

• ev: String, specifies the name of the event
• func: Function, specify the event processing function

Return results:

• Object, returns the event object itself to facilitate chain calls

---

Cancel all functions in the object processing queue

1
Object FSWatcher.off(String ev);

Call parameters:

• ev: String, specifies the name of the event

Return results:

• Object, returns the event object itself to facilitate chain calls

---

Unassign a function from the object processing queue

1
Object FSWatcher.off(Object map);

Call parameters:

• map: Object, specifies the event mapping relationship, the object attribute name is used as the event name, and the value of the attribute is used as the event processing function

Return results:

• Object, returns the event object itself to facilitate chain calls

---

removeListener

Unassign a function from the object processing queue

1
2
Object FSWatcher.removeListener(String ev,
    Function func);

Call parameters:

• ev: String, specifies the name of the event
• func: Function, specify the event processing function

Return results:

• Object, returns the event object itself to facilitate chain calls

---

Cancel all functions in the object processing queue

1
Object FSWatcher.removeListener(String ev);

Call parameters:

• ev: String, specifies the name of the event

Return results:

• Object, returns the event object itself to facilitate chain calls

---

Unassign a function from the object processing queue

1
Object FSWatcher.removeListener(Object map);

Call parameters:

• map: Object, specifies the event mapping relationship, the object attribute name is used as the event name, and the value of the attribute is used as the event processing function

Return results:

• Object, returns the event object itself to facilitate chain calls

---

removeAllListeners

Cancels all listeners for all events from the object's processing queue. If an event is specified, removes all listeners for the specified event.

1
Object FSWatcher.removeAllListeners(String ev);

Call parameters:

• ev: String, specifies the name of the event

Return results:

• Object, returns the event object itself to facilitate chain calls

---

Cancels all listeners for all events from the object's processing queue. If an event is specified, removes all listeners for the specified event.

1
Object FSWatcher.removeAllListeners(Array evs = []);

Call parameters:

• evs: Array, specify the name of the event

Return results:

• Object, returns the event object itself to facilitate chain calls

---

setMaxListeners

The default limit on the number of listeners, for compatibility only

1
FSWatcher.setMaxListeners(Integer n);

Call parameters:

• n: Integer, specify the number of events

---

getMaxListeners

Gets the default limit number of listeners, for compatibility only

1
Integer FSWatcher.getMaxListeners();

Return results:

• Integer, returns the default limit quantity

---

listeners

Query the listener array for the specified event of the object

1
Array FSWatcher.listeners(String ev);

Call parameters:

• ev: String, specifies the name of the event

Return results:

• Array, returns the listener array for the specified event

---

listenerCount

Query the number of listeners for the specified event of the object

1
Integer FSWatcher.listenerCount(String ev);

Call parameters:

• ev: String, specifies the name of the event

Return results:

• Integer, returns the number of listeners for the specified event

---

Query the number of listeners for the specified event of the object

1
2
Integer FSWatcher.listenerCount(Value o,
    String ev);

Call parameters:

• o: Value, specifies the object of the query
• ev: String, specifies the name of the event

Return results:

• Integer, returns the number of listeners for the specified event

---

eventNames

Query listener event name

1
Array FSWatcher.eventNames();

Return results:

• Array, returns an array of event names

---

emit

Actively trigger an event

1
2
Boolean FSWatcher.emit(String ev,
    ...args);

Call parameters:

• ev: String, event name
• args: ..., event parameters will be passed to the event processing function

Return results:

• Boolean, returns the event trigger status, returns true if there is a response event, otherwise returns false

---

toString

Returns the string representation of the object. Generally, "[Native Object]" is returned. The object can be re-implemented according to its own characteristics.

1
String FSWatcher.toString();

Return results:

• String, returns the string representation of the object

---

toJSON

Returns a JSON format representation of the object, generally returning a collection of readable properties defined by the object.

1
Value FSWatcher.toJSON(String key = "");

Call parameters:

• key: String, not used

Return results:

• Value, returns a value containing JSON serializable