blob: 487258922cedf2d0646d86403a03e0a9c3eb2f0a [file] [log] [blame]
var len = 0;
export default function asap(callback, arg) {
queue[len] = callback;
queue[len + 1] = arg;
len += 2;
if (len === 2) {
// If len is 1, that means that we need to schedule an async flush.
// If additional callbacks are queued before the queue is flushed, they
// will be processed by this flush that we are scheduling.
scheduleFlush();
}
}
var browserGlobal = (typeof window !== 'undefined') ? window : {};
var BrowserMutationObserver = browserGlobal.MutationObserver || browserGlobal.WebKitMutationObserver;
// test for web worker but not in IE10
var isWorker = typeof Uint8ClampedArray !== 'undefined' &&
typeof importScripts !== 'undefined' &&
typeof MessageChannel !== 'undefined';
// node
function useNextTick() {
return function() {
process.nextTick(flush);
};
}
function useMutationObserver() {
var iterations = 0;
var observer = new BrowserMutationObserver(flush);
var node = document.createTextNode('');
observer.observe(node, { characterData: true });
return function() {
node.data = (iterations = ++iterations % 2);
};
}
// web worker
function useMessageChannel() {
var channel = new MessageChannel();
channel.port1.onmessage = flush;
return function () {
channel.port2.postMessage(0);
};
}
function useSetTimeout() {
return function() {
setTimeout(flush, 1);
};
}
var queue = new Array(1000);
function flush() {
for (var i = 0; i < len; i+=2) {
var callback = queue[i];
var arg = queue[i+1];
callback(arg);
queue[i] = undefined;
queue[i+1] = undefined;
}
len = 0;
}
var scheduleFlush;
// Decide what async method to use to triggering processing of queued callbacks:
if (typeof process !== 'undefined' && {}.toString.call(process) === '[object process]') {
scheduleFlush = useNextTick();
} else if (BrowserMutationObserver) {
scheduleFlush = useMutationObserver();
} else if (isWorker) {
scheduleFlush = useMessageChannel();
} else {
scheduleFlush = useSetTimeout();
}