Immediate.tsā¢1.17 kB
let nextHandle = 1;
// The promise needs to be created lazily otherwise it won't be patched by Zones
let resolved: Promise<any>;
const activeHandles: { [key: number]: any } = {};
/**
* Finds the handle in the list of active handles, and removes it.
* Returns `true` if found, `false` otherwise. Used both to clear
* Immediate scheduled tasks, and to identify if a task should be scheduled.
*/
function findAndClearHandle(handle: number): boolean {
if (handle in activeHandles) {
delete activeHandles[handle];
return true;
}
return false;
}
/**
* Helper functions to schedule and unschedule microtasks.
*/
export const Immediate = {
setImmediate(cb: () => void): number {
const handle = nextHandle++;
activeHandles[handle] = true;
if (!resolved) {
resolved = Promise.resolve();
}
resolved.then(() => findAndClearHandle(handle) && cb());
return handle;
},
clearImmediate(handle: number): void {
findAndClearHandle(handle);
},
};
/**
* Used for internal testing purposes only. Do not export from library.
*/
export const TestTools = {
pending() {
return Object.keys(activeHandles).length;
}
};