GitHub
TwitterenqueueByQueue
Enqueue a multiple tasks within multiple queues within a batch.
queues.enqueueByQueue( fnByQueue [, context [, args [, makeMeta [, reasonLog ]]]] )
enqueueByQueue is a helper that enqueues multiple tasks within queues at one time. It assumes
all tasks share the same context and arguments.
const ran = [];
canQueues.enqueueByQueue( {
"notify": [ function notify() {
ran.push( "notify" );
} ],
"derive": [
function derive1() {
ran.push( "derive1" );
},
function derive2() {
ran.push( "derive2" );
}
],
"domUI": [ function domUI() {
ran.push( "domUI" );
} ],
"mutate": [ function domUI() {
ran.push( "mutate" );
} ]
} );
console.log( ran ); // -> ["notify", "derive1", "derive2", "domUI", "mutate"]
enqueueByQueue uses batch.start and batch.stop to flush tasks only after
all tasks have been enqueued.
Parameters
- fnByQueue
{Object}:An object with keys of "notify", "derive", "domUI", and/or "mutate" that have Arrays of Functions (
tasks) as a value. - context
{Object}:The
thiscontext to call eachtaskfn with. - args
{Array}:The arguments to
applyto each task fn. - makeMeta
{function(task, context, args)}:A function that takes (
task,context,args) and returns an Object that will be themetaargument when the task is called. If nomakeMetais provided an empty meta object will be created. - reasonLog
{Array}:A property attached to the
metaobject asmeta.reasonLogbeforetaskis called.
Use
enqueueByQueue together with can-key-tree is used by many modules within CanJS to dispatch event handlers in their requested queues. can-key-tree is used to organize event handlers by key and queue as follows:
const observable = {
handlers: new KeyTree( [ Object, Object, Array ] ),
[ canSymbol.for( "can.onKeyValue" ) ]: function( key, handler, queue ) {
this.handlers.add( [ key, queue || "mutate", handler ] );
},
[ canSymbol.for( "can.offKeyValue" ) ]: function( key, handler, queue ) {
this.handlers.delete( [ key, queue || "mutate", handler ] );
}
// ...
};
When a change happens to one of the keys, enqueueByQueue is useful for enqueueing those event handlers:
const observable = {
// ...
dispatch: function( key, newVal, oldVal ) {
const fnByQueue = this.handlers.getNode( [ key ] );
queues.enqueueByQueue( fnByQueue, this, [ newVal, oldVal ], null
//!steal-remove-start
/* jshint laxcomma: true */
, [ canReflect.getName( this ) + "'s", key, "changed to", newVal ],
/* jshint laxcomma: false */
//!steal-remove-end
);
}
};