Object built-in object

Object LruCache

LRU (least recently used) cache object

LruCache is used to maintain an LRU cache, the creation method:

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var util = require("util"); var c = new util.LruCache(10, 100);

Inheritance

Constructor

LruCache

LruCache object constructor

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new LruCache(Integer size, Integer timeout = 0);

Call parameters:

  • size : Integer, the maximum size of the cache
  • timeout : Integer, element expiration time, unit is ms, no expiration if less than or equal to 0, default is 0

Static properties

defaultMaxListeners

Integer, the default global maximum number of listeners

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static Integer LruCache.defaultMaxListeners;

Member attributes

size

Integer, query the number of values ​​in the container

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readonly Integer LruCache.size;

timeout

Integer, query and set the expiration time of the elements in the container, the unit is ms, no failure if less than or equal to 0

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Integer LruCache.timeout;

onexpire

Function, query and bind data timeout event, equivalent to on("expire", func);

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Function LruCache.onexpire;

Member function

clear

Clear container data

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LruCache.clear();

has

Check whether there is data with the specified key value in the container

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Boolean LruCache.has(String name);

Call parameters:

  • name : String, specify the key value to be checked

Return result:

  • Boolean , returns whether the key value exists

get

Query the value of the specified key

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Value LruCache.get(String name);

Call parameters:

  • name : String, specify the key value to be queried

Return result:

  • Value , returns the value corresponding to the key value, if it does not exist, returns undefined

Query the value of the specified key value, if it does not exist or expires, call the callback function to update the data

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Value LruCache.get(String name, Function updater);

Call parameters:

  • name : String, specify the key value to be queried
  • updater : Function, specify the update function

Return result:

  • Value , returns the value corresponding to the key value

set

Set a key value data, insert a new data if the key value does not exist

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LruCache.set(String name, Value value);

Call parameters:

  • name : String, specify the key value to be set
  • value : Value, specify the data to be set

Set a key value data, insert new data if the key value does not exist

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LruCache.set(Object map);

Call parameters:

  • map : Object, specify the key value data dictionary to be set

remove

Delete all values ​​of the specified key

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LruCache.remove(String name);

Call parameters:

  • name : String, specify the key to be deleted

isEmpty

Check if the container is empty

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Boolean LruCache.isEmpty();

Return result:

  • Boolean , return true if there is no value in the container

on

Bind an event handler to the object

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Object LruCache.on(String ev, Function func);

Call parameters:

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

Return result:

  • Object , returns the event object itself, easy to chain call

Bind an event handler to the object

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Object LruCache.on(Object map);

Call parameters:

  • map : Object, specify the event mapping relationship, the object property name will be the event name, and the property value will be the event processing function

Return result:

  • Object , returns the event object itself, easy to chain call

addListener

Bind an event handler to the object

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Object LruCache.addListener(String ev, Function func);

Call parameters:

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

Return result:

  • Object , returns the event object itself, easy to chain call

Bind an event handler to the object

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Object LruCache.addListener(Object map);

Call parameters:

  • map : Object, specify the event mapping relationship, the object property name will be the event name, and the property value will be the event processing function

Return result:

  • Object , returns the event object itself, easy to chain call

prependListener

Bind an event handler to the object start

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Object LruCache.prependListener(String ev, Function func);

Call parameters:

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

Return result:

  • Object , returns the event object itself, easy to chain call

Bind an event handler to the object start

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Object LruCache.prependListener(Object map);

Call parameters:

  • map : Object, specify the event mapping relationship, the object property name will be the event name, and the property value will be the event processing function

Return result:

  • Object , returns the event object itself, easy to chain call

once

Bind a one-time event processing function to the object, the one-time processing function will only be triggered once

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Object LruCache.once(String ev, Function func);

Call parameters:

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

Return result:

  • Object , returns the event object itself, easy to chain call

Bind a one-time event processing function to the object, the one-time processing function will only be triggered once

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Object LruCache.once(Object map);

Call parameters:

  • map : Object, specify the event mapping relationship, the object property name will be the event name, and the property value will be the event processing function

Return result:

  • Object , returns the event object itself, easy to chain call

prependOnceListener

Bind an event handler to the object start

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Object LruCache.prependOnceListener(String ev, Function func);

Call parameters:

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

Return result:

  • Object , returns the event object itself, easy to chain call

Bind an event handler to the object start

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Object LruCache.prependOnceListener(Object map);

Call parameters:

  • map : Object, specify the event mapping relationship, the object property name will be the event name, and the property value will be the event processing function

Return result:

  • Object , returns the event object itself, easy to chain call

off

Cancel the specified function from the object processing queue

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Object LruCache.off(String ev, Function func);

Call parameters:

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

Return result:

  • Object , returns the event object itself, easy to chain call

Cancel all functions in the object processing queue

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Object LruCache.off(String ev);

Call parameters:

  • ev : String, specify the name of the event

Return result:

  • Object , returns the event object itself, easy to chain call

Cancel the specified function from the object processing queue

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Object LruCache.off(Object map);

Call parameters:

  • map : Object, specify the event mapping relationship, the object property name is used as the event name, and the property value is used as the event processing function

Return result:

  • Object , returns the event object itself, easy to chain call

removeListener

Cancel the specified function from the object processing queue

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Object LruCache.removeListener(String ev, Function func);

Call parameters:

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

Return result:

  • Object , returns the event object itself, easy to chain call

Cancel all functions in the object processing queue

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Object LruCache.removeListener(String ev);

Call parameters:

  • ev : String, specify the name of the event

Return result:

  • Object , returns the event object itself, easy to chain call

Cancel the specified function from the object processing queue

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Object LruCache.removeListener(Object map);

Call parameters:

  • map : Object, specify the event mapping relationship, the object property name is used as the event name, and the property value is used as the event processing function

Return result:

  • Object , returns the event object itself, easy to chain call

removeAllListeners

Cancel all listeners of all events from the object processing queue. If an event is specified, remove all listeners of the specified event.

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Object LruCache.removeAllListeners(Array evs = []);

Call parameters:

  • evs : Array, specify the name of the event

Return result:

  • Object , returns the event object itself, easy to chain call

setMaxListeners

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

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LruCache.setMaxListeners(Integer n);

Call parameters:

  • n : Integer, specify the number of events

getMaxListeners

Get the default limit of the number of listeners, only for compatibility

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Integer LruCache.getMaxListeners();

Return result:

  • Integer , returns the default limit number

listeners

Array of listeners for the specified event of the query object

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Array LruCache.listeners(String ev);

Call parameters:

  • ev : String, specify the name of the event

Return result:

  • Array , returns an array of listeners for the specified event

listenerCount

The number of listeners for the specified event of the query object

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Integer LruCache.listenerCount(String ev);

Call parameters:

  • ev : String, specify the name of the event

Return result:

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

eventNames

Query listener event name

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Array LruCache.eventNames();

Return result:

  • Array , returns an array of event names

emit

Actively trigger an event

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Boolean LruCache.emit(String ev, ...args);

Call parameters:

  • ev : String, event name
  • args : ..., event parameters, which will be passed to the event handler

Return result:

  • 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 returns "[Native Object]", the object can be re-implemented according to its own characteristics

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String LruCache.toString();

Return result:

  • String , returns the string representation of the object

toJSON

Returns the JSON format representation of the object, generally returns a collection of readable attributes defined by the object

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Value LruCache.toJSON(String key = "");

Call parameters:

  • key : String, unused

Return result:

  • Value , returns a value containing JSON serializable