asynchronous-map v0.0.1
asynchronous-map
A simple key/value map, where the values are loaded asynchronously.
Backed by JS native Map and like Map, any value (both objects and primitive values) may be used as either a key or a value.
Installation
Install via npm
$ npm install asynchronous-map --saveUsage
var AsyncMap = require('asynchronous-map');
var userMap = new AsyncMap(function(key, callback) {
// Fetch data for key asynchronously (From a database, remote API etc.)
...
callback(null, value);
});
var userId1 = 'U1234';
userMap.get(userId1, function(err, value) {
console.log(value);
});Methods
Constructor
AsyncMap(sourcer)
Parameters
sourcer(key, callback)- Function that returns the value for thekeyvia callback. The sourcer function is passed akeyand acallback(err, value).
Return value
Returns a newly created AsyncMap object.
clear
Removes all elements in the Map object.
Parameters
None.
delete
removes the specified element in the Map object.
Parameters
key- Required. The key of the element to remove from the Map object.
Return value
Returns true if an element in the Map object existed and has been removed, or false if the element does not exist.
get
Returns a specified element from a Map object. If the value not exists in the Map, it is fetched via the sourcer.
Parameters
key- Required. The key of the element to remove from the Map object.callback(err, value)- Required. A callback which is called with the value for the key.
Return value
Returns this to support fluent interface.
has
Checks if the key exists in the map. This does not automatically fetch the value.
Parameters
key- Required. The key of the element to remove from the Map object.
Return value
Returns true if an element with the specified key exists in the Map object; otherwise false.
keys
Same as Map.keys.
Parameters
- none.
Return value
Returns a new Iterator object that contains the keys for each element in the Map object in insertion order.
set
Forces to fetch/refresh data via sourcer.
Parameters
key- Required. The key of the element to remove from the Map object.callback(err, value)- Optional. A callback which is called with the value for the key.
Return value
Returns this to support fluent interface.
size
Calculates the number of elements in a Map object.
Parameters
None.
Return value
Returns the number of elements in a Map object.
License
8 years ago