@effection/core - npm Package Compare versions

Comparing version 2.0.0-preview.2-ed0bed9 to 2.0.0-preview.3-2febf01

CHANGELOG.md

 # @effection/core
 
+## 2.0.0-preview.3
+
+### Patch Changes
+
+- bdedf68: Simplify sleep method
+- 2bf5ef4: Make iterator controllers reentrant so they can e.g. halt themselves
+
 ## 2.0.0-preview.2
@@ -4,0 +11,0 @@

dist/controller/iterator-controller.d.ts

@@ -6,2 +6,3 @@ import { Controller } from './controller';
 import { Trapper } from '../trapper';
+declare type Continuation = () => IteratorResult<Operation<unknown>>;
 export declare class IteratorController<TOut> implements Controller<TOut>, Trapper {
@@ -11,8 +12,12 @@ private controls;
     private didHalt;
+    private didEnter;
     private subTask?;
+    private continuations;
     constructor(controls: Controls<TOut>, iterator: OperationIterator<TOut>);
     start(): Promise<void>;
-    resume(iter: () => IteratorResult<Operation<unknown>>): void;
+    resume(iter: Continuation): void;
+    step(iter: Continuation): void;
     trap(child: Task): void;
     halt(): void;
 }
+export {};

dist/core.cjs.development.js

@@ -228,2 +228,4 @@ 'use strict';
     this.didHalt = false;
+    this.didEnter = false;
+    this.continuations = [];
   } // make this an async function to delay the first iteration until the next event loop tick
@@ -246,5 +248,27 @@
     }
+  } // the purpose of this method is solely to make `step` reentrant, that is we
+  // should be able to handle a `halt` which occurs while we are already in a
+  // generator. This is a rare case and should only happen under some edge
+  // cases, for example a task halting itself, or a task causing one of its
+  // siblings to fail.
+  ;
+
+  _proto.resume = function resume(iter) {
+    this.continuations.push(iter); // only enter this loop if we aren't already running it
+
+    if (!this.didEnter) {
+      this.didEnter = true; // acquire lock
+      // use while loop since collection can be modified during iteration
+
+      var continuation;
+
+      while (continuation = this.continuations.shift()) {
+        this.step(continuation);
+      }
+
+      this.didEnter = false; // release lock
+    }
   };
 
-  _proto.resume = function resume(iter) {
+  _proto.step = function step(iter) {
     var next;
@@ -694,2 +718,9 @@
     }
+  },
+  halt: function halt() {
+    try {
+      return Promise.resolve(Effection.root.halt()).then(function () {});
+    } catch (e) {
+      return Promise.reject(e);
+    }
   }
@@ -703,5 +734,3 @@ };
       task.ensure(function () {
-        if (timeoutId) {
-          clearTimeout(timeoutId);
-        }
+        return clearTimeout(timeoutId);
       });
@@ -708,0 +737,0 @@ };

dist/core.cjs.production.min.js

@@ -1,2 +0,2 @@
-"use strict";var t=require("events");function r(t,r){for(var e=0;e<r.length;e++){var n=r[e];n.enumerable=n.enumerable||!1,n.configurable=!0,"value"in n&&(n.writable=!0),Object.defineProperty(t,n.key,n)}}function e(t,e,n){return e&&r(t.prototype,e),n&&r(t,n),t}function n(t,r){t.prototype=Object.create(r.prototype),t.prototype.constructor=t,o(t,r)}function i(t){return(i=Object.setPrototypeOf?Object.getPrototypeOf:function(t){return t.__proto__||Object.getPrototypeOf(t)})(t)}function o(t,r){return(o=Object.setPrototypeOf||function(t,r){return t.__proto__=r,t})(t,r)}function s(){if("undefined"==typeof Reflect||!Reflect.construct)return!1;if(Reflect.construct.sham)return!1;if("function"==typeof Proxy)return!0;try{return Boolean.prototype.valueOf.call(Reflect.construct(Boolean,[],(function(){}))),!0}catch(t){return!1}}function c(t,r,e){return(c=s()?Reflect.construct:function(t,r,e){var n=[null];n.push.apply(n,r);var i=new(Function.bind.apply(t,n));return e&&o(i,e.prototype),i}).apply(null,arguments)}function a(t){var r="function"==typeof Map?new Map:void 0;return(a=function(t){if(null===t||-1===Function.toString.call(t).indexOf("[native code]"))return t;if("function"!=typeof t)throw new TypeError("Super expression must either be null or a function");if(void 0!==r){if(r.has(t))return r.get(t);r.set(t,e)}function e(){return c(t,arguments,i(this).constructor)}return e.prototype=Object.create(t.prototype,{constructor:{value:e,enumerable:!1,writable:!0,configurable:!0}}),o(e,t)})(t)}var u=function(){function t(t){this.controls=t}var r=t.prototype;return r.start=function(){},r.halt=function(){this.controls.halted()},t}();function h(){var t=function(){},r=function(){},e=new Promise((function(e,n){t=e,r=n}));return{resolve:t,reject:r,promise:e}}var l=Symbol("halt"),f=function(){function t(t,r){this.controls=t,this.promise=r,this.haltSignal=h()}var r=t.prototype;return r.start=function(){var t=this;Promise.race([this.promise,this.haltSignal.promise]).then((function(r){r===l?t.controls.halted():t.controls.resolve(r)}),(function(r){t.controls.reject(r)}))},r.halt=function(){this.haltSignal.resolve(l)},t}();function p(t){return t&&"function"==typeof t.then}var d=function(t){function r(){return t.call(this,"halted")||this}return n(r,t),e(r,[{key:"__isEffectionHaltError",get:function(){return!0}}]),r}(a(Error));function v(t){var r;if(!(r=t)||!r.__isEffectionHaltError)throw t}var m=function(){function t(t,r){this.controls=t,this.iterator=r,this.didHalt=!1}var r=t.prototype;return r.start=function(){try{var t=this;return t.resume((function(){return t.iterator.next()})),Promise.resolve()}catch(t){return Promise.reject(t)}},r.resume=function(t){var r;try{r=t()}catch(t){return void this.controls.reject(t)}r.done?this.didHalt?this.controls.halted():this.controls.resolve(r.value):(this.subTask=new E(r.value),this.subTask.addTrapper(this),this.subTask.start())},r.trap=function(t){var r=this;"completed"===t.state&&this.resume((function(){return r.iterator.next(t.result)})),"errored"===t.state&&this.resume((function(){return r.iterator.throw(t.error)})),"halted"===t.state&&this.resume((function(){return r.iterator.throw(new d)}))},r.halt=function(){var t=this;this.didHalt||(this.didHalt=!0,this.subTask&&(this.subTask.removeTrapper(this),this.subTask.halt()),this.resume((function(){return t.iterator.return(void 0)})))},t}(),g=function(){function t(t,r){this.controls=t,this.resolution=r}var r=t.prototype;return r.start=function(){try{this.resolution(this.controls.resolve,this.controls.reject)}catch(t){this.controls.reject(t)}},r.halt=function(){this.controls.halted()},t}(),y=function(){function t(t,r){this.controls=t,this.operation=r}var r=t.prototype;return r.start=function(t){var r,e;try{r=this.operation(t)}catch(t){return void this.controls.reject(t)}e=p(r)?new f(this.controls,r):"function"==typeof r?new g(this.controls,r):new m(this.controls,r),this.controller=e,e.start()},r.halt=function(){try{if(!this.controller)throw new Error("INTERNAL ERROR: halt called before start, this should never happen");return this.controller.halt(),Promise.resolve()}catch(t){return Promise.reject(t)}},t}();function w(t){return JSON.stringify(t)}var b=function(){function t(t){this.emitter=t,this.current="pending"}var r=t.prototype;return r.transition=function(t,r){var e=this.current,n=r[e];if(!n){var i=Object.keys(r).map(w).join(", ");throw new Error("INTERNAL ERROR: state transition "+w(t)+" is not valid in current state "+w(e)+", should be one of "+i)}this.current=n,this.emitter.emit("state",{from:e,to:n})},r.start=function(){this.transition("start",{pending:"running"})},r.resolve=function(){this.transition("resolve",{running:"completing",completing:"completing",erroring:"erroring",halting:"halting"})},r.reject=function(){this.transition("reject",{running:"erroring",completing:"erroring",halting:"erroring",erroring:"erroring"})},r.halt=function(){this.transition("halt",{running:"halting",completing:"halting",halting:"halting",erroring:"erroring",halted:"halted",completed:"completed",errored:"errored"})},r.finish=function(){this.transition("finish",{completing:"completed",erroring:"errored",halting:"halted"})},e(t,[{key:"isFinishing",get:function(){return["completing","halting","erroring"].includes(this.current)}}]),t}(),j=0,E=function(t){function r(r,e){var n;if(void 0===e&&(e={}),(n=t.call(this)||this).operation=r,n.options=e,n.id=++j,n.children=new Set,n.trappers=new Set,n.ensureHandlers=new Set,n.deferred=h(),n.stateMachine=new b(function(t){if(void 0===t)throw new ReferenceError("this hasn't been initialised - super() hasn't been called");return t}(n)),n.controls={resolve:function(t){n.stateMachine.resolve(),n.result=t,n.children.forEach((function(t){t.options.blockParent||t.halt()})),n.resume()},reject:function(t){n.stateMachine.reject(),n.result=void 0,n.error=t,n.children.forEach((function(t){return t.halt()})),n.resume()},halted:function(){n.stateMachine.halt(),n.children.forEach((function(t){return t.halt()})),n.resume()}},r)if(p(r))n.controller=new f(n.controls,r);else{if("function"!=typeof r)throw new Error("unkown type of operation: "+r);n.controller=new y(n.controls,r)}else n.controller=new u(n.controls);return n.deferred.promise.catch((function(){})),n}n(r,t);var i=r.prototype;return i.start=function(){this.stateMachine.start(),this.controller.start(this)},i.resume=function(){var t=this;this.stateMachine.isFinishing&&0===this.children.size&&(this.stateMachine.finish(),this.ensureHandlers.forEach((function(t){return t()})),this.trappers.forEach((function(r){return r.trap(t)})),"completed"===this.state?this.deferred.resolve(this.result):"halted"===this.state?this.deferred.reject(new d):"errored"===this.state&&this.deferred.reject(this.error))},i.then=function(t,r){return this.deferred.promise.then(t,r)},i.catch=function(t){return this.deferred.promise.catch(t)},i.catchHalt=function(){return this.deferred.promise.catch(v)},i.finally=function(t){return this.deferred.promise.finally(t)},i.spawn=function(t,e){if("running"!==this.state)throw new Error("cannot spawn a child on a task which is not running");var n=new r(t,e);return this.link(n),n.start(),n},i.link=function(t){this.children.has(t)||(t.addTrapper(this),this.children.add(t),this.emit("link",t))},i.unlink=function(t){this.children.has(t)&&(t.removeTrapper(this),this.children.delete(t),this.emit("unlink",t))},i.trap=function(t){this.children.has(t)&&("errored"!==t.state||this.options.ignoreChildErrors||this.controls.reject(t.error),this.unlink(t)),this.resume()},i.ensure=function(t){this.ensureHandlers.add(t)},i.addTrapper=function(t){this.trappers.add(t)},i.removeTrapper=function(t){this.trappers.delete(t)},i.halt=function(){try{return this.controller.halt(),Promise.resolve(this.catch((function(){}))).then((function(){}))}catch(t){return Promise.reject(t)}},e(r,[{key:"state",get:function(){return this.stateMachine.current}},{key:Symbol.toStringTag,get:function(){return"[Task "+this.id+"]"}}]),r}(t.EventEmitter);function k(){var t=new E(void 0,{ignoreChildErrors:!0});return t.start(),t}var T={root:k(),reset:function(){try{return Promise.resolve(T.root.halt()).then((function(){T.root=k()}))}catch(t){return Promise.reject(t)}}};exports.Deferred=h,exports.Effection=T,exports.Task=E,exports.deprecated=function(t,r){return function(){try{throw new Error("trace")}catch(r){var e=r.stack.split("\n").slice(3,4),n=e[0];console.warn(t,"\n"+n)}for(var i=arguments.length,o=new Array(i),s=0;s<i;s++)o[s]=arguments[s];return r.call.apply(r,[this].concat(o))}},exports.run=function(t,r){return T.root.spawn(t,r)},exports.sleep=function(t){return function(r){return function(e){var n=setTimeout(e,t);r.ensure((function(){n&&clearTimeout(n)}))}}};
+"use strict";var t=require("events");function r(t,r){for(var e=0;e<r.length;e++){var n=r[e];n.enumerable=n.enumerable||!1,n.configurable=!0,"value"in n&&(n.writable=!0),Object.defineProperty(t,n.key,n)}}function e(t,e,n){return e&&r(t.prototype,e),n&&r(t,n),t}function n(t,r){t.prototype=Object.create(r.prototype),t.prototype.constructor=t,o(t,r)}function i(t){return(i=Object.setPrototypeOf?Object.getPrototypeOf:function(t){return t.__proto__||Object.getPrototypeOf(t)})(t)}function o(t,r){return(o=Object.setPrototypeOf||function(t,r){return t.__proto__=r,t})(t,r)}function s(){if("undefined"==typeof Reflect||!Reflect.construct)return!1;if(Reflect.construct.sham)return!1;if("function"==typeof Proxy)return!0;try{return Boolean.prototype.valueOf.call(Reflect.construct(Boolean,[],(function(){}))),!0}catch(t){return!1}}function c(t,r,e){return(c=s()?Reflect.construct:function(t,r,e){var n=[null];n.push.apply(n,r);var i=new(Function.bind.apply(t,n));return e&&o(i,e.prototype),i}).apply(null,arguments)}function a(t){var r="function"==typeof Map?new Map:void 0;return(a=function(t){if(null===t||-1===Function.toString.call(t).indexOf("[native code]"))return t;if("function"!=typeof t)throw new TypeError("Super expression must either be null or a function");if(void 0!==r){if(r.has(t))return r.get(t);r.set(t,e)}function e(){return c(t,arguments,i(this).constructor)}return e.prototype=Object.create(t.prototype,{constructor:{value:e,enumerable:!1,writable:!0,configurable:!0}}),o(e,t)})(t)}var u=function(){function t(t){this.controls=t}var r=t.prototype;return r.start=function(){},r.halt=function(){this.controls.halted()},t}();function h(){var t=function(){},r=function(){},e=new Promise((function(e,n){t=e,r=n}));return{resolve:t,reject:r,promise:e}}var l=Symbol("halt"),f=function(){function t(t,r){this.controls=t,this.promise=r,this.haltSignal=h()}var r=t.prototype;return r.start=function(){var t=this;Promise.race([this.promise,this.haltSignal.promise]).then((function(r){r===l?t.controls.halted():t.controls.resolve(r)}),(function(r){t.controls.reject(r)}))},r.halt=function(){this.haltSignal.resolve(l)},t}();function p(t){return t&&"function"==typeof t.then}var d=function(t){function r(){return t.call(this,"halted")||this}return n(r,t),e(r,[{key:"__isEffectionHaltError",get:function(){return!0}}]),r}(a(Error));function v(t){var r;if(!(r=t)||!r.__isEffectionHaltError)throw t}var m=function(){function t(t,r){this.controls=t,this.iterator=r,this.didHalt=!1,this.didEnter=!1,this.continuations=[]}var r=t.prototype;return r.start=function(){try{var t=this;return t.resume((function(){return t.iterator.next()})),Promise.resolve()}catch(t){return Promise.reject(t)}},r.resume=function(t){if(this.continuations.push(t),!this.didEnter){var r;for(this.didEnter=!0;r=this.continuations.shift();)this.step(r);this.didEnter=!1}},r.step=function(t){var r;try{r=t()}catch(t){return void this.controls.reject(t)}r.done?this.didHalt?this.controls.halted():this.controls.resolve(r.value):(this.subTask=new j(r.value),this.subTask.addTrapper(this),this.subTask.start())},r.trap=function(t){var r=this;"completed"===t.state&&this.resume((function(){return r.iterator.next(t.result)})),"errored"===t.state&&this.resume((function(){return r.iterator.throw(t.error)})),"halted"===t.state&&this.resume((function(){return r.iterator.throw(new d)}))},r.halt=function(){var t=this;this.didHalt||(this.didHalt=!0,this.subTask&&(this.subTask.removeTrapper(this),this.subTask.halt()),this.resume((function(){return t.iterator.return(void 0)})))},t}(),g=function(){function t(t,r){this.controls=t,this.resolution=r}var r=t.prototype;return r.start=function(){try{this.resolution(this.controls.resolve,this.controls.reject)}catch(t){this.controls.reject(t)}},r.halt=function(){this.controls.halted()},t}(),y=function(){function t(t,r){this.controls=t,this.operation=r}var r=t.prototype;return r.start=function(t){var r,e;try{r=this.operation(t)}catch(t){return void this.controls.reject(t)}e=p(r)?new f(this.controls,r):"function"==typeof r?new g(this.controls,r):new m(this.controls,r),this.controller=e,e.start()},r.halt=function(){try{if(!this.controller)throw new Error("INTERNAL ERROR: halt called before start, this should never happen");return this.controller.halt(),Promise.resolve()}catch(t){return Promise.reject(t)}},t}();function w(t){return JSON.stringify(t)}var b=function(){function t(t){this.emitter=t,this.current="pending"}var r=t.prototype;return r.transition=function(t,r){var e=this.current,n=r[e];if(!n){var i=Object.keys(r).map(w).join(", ");throw new Error("INTERNAL ERROR: state transition "+w(t)+" is not valid in current state "+w(e)+", should be one of "+i)}this.current=n,this.emitter.emit("state",{from:e,to:n})},r.start=function(){this.transition("start",{pending:"running"})},r.resolve=function(){this.transition("resolve",{running:"completing",completing:"completing",erroring:"erroring",halting:"halting"})},r.reject=function(){this.transition("reject",{running:"erroring",completing:"erroring",halting:"erroring",erroring:"erroring"})},r.halt=function(){this.transition("halt",{running:"halting",completing:"halting",halting:"halting",erroring:"erroring",halted:"halted",completed:"completed",errored:"errored"})},r.finish=function(){this.transition("finish",{completing:"completed",erroring:"errored",halting:"halted"})},e(t,[{key:"isFinishing",get:function(){return["completing","halting","erroring"].includes(this.current)}}]),t}(),E=0,j=function(t){function r(r,e){var n;if(void 0===e&&(e={}),(n=t.call(this)||this).operation=r,n.options=e,n.id=++E,n.children=new Set,n.trappers=new Set,n.ensureHandlers=new Set,n.deferred=h(),n.stateMachine=new b(function(t){if(void 0===t)throw new ReferenceError("this hasn't been initialised - super() hasn't been called");return t}(n)),n.controls={resolve:function(t){n.stateMachine.resolve(),n.result=t,n.children.forEach((function(t){t.options.blockParent||t.halt()})),n.resume()},reject:function(t){n.stateMachine.reject(),n.result=void 0,n.error=t,n.children.forEach((function(t){return t.halt()})),n.resume()},halted:function(){n.stateMachine.halt(),n.children.forEach((function(t){return t.halt()})),n.resume()}},r)if(p(r))n.controller=new f(n.controls,r);else{if("function"!=typeof r)throw new Error("unkown type of operation: "+r);n.controller=new y(n.controls,r)}else n.controller=new u(n.controls);return n.deferred.promise.catch((function(){})),n}n(r,t);var i=r.prototype;return i.start=function(){this.stateMachine.start(),this.controller.start(this)},i.resume=function(){var t=this;this.stateMachine.isFinishing&&0===this.children.size&&(this.stateMachine.finish(),this.ensureHandlers.forEach((function(t){return t()})),this.trappers.forEach((function(r){return r.trap(t)})),"completed"===this.state?this.deferred.resolve(this.result):"halted"===this.state?this.deferred.reject(new d):"errored"===this.state&&this.deferred.reject(this.error))},i.then=function(t,r){return this.deferred.promise.then(t,r)},i.catch=function(t){return this.deferred.promise.catch(t)},i.catchHalt=function(){return this.deferred.promise.catch(v)},i.finally=function(t){return this.deferred.promise.finally(t)},i.spawn=function(t,e){if("running"!==this.state)throw new Error("cannot spawn a child on a task which is not running");var n=new r(t,e);return this.link(n),n.start(),n},i.link=function(t){this.children.has(t)||(t.addTrapper(this),this.children.add(t),this.emit("link",t))},i.unlink=function(t){this.children.has(t)&&(t.removeTrapper(this),this.children.delete(t),this.emit("unlink",t))},i.trap=function(t){this.children.has(t)&&("errored"!==t.state||this.options.ignoreChildErrors||this.controls.reject(t.error),this.unlink(t)),this.resume()},i.ensure=function(t){this.ensureHandlers.add(t)},i.addTrapper=function(t){this.trappers.add(t)},i.removeTrapper=function(t){this.trappers.delete(t)},i.halt=function(){try{return this.controller.halt(),Promise.resolve(this.catch((function(){}))).then((function(){}))}catch(t){return Promise.reject(t)}},e(r,[{key:"state",get:function(){return this.stateMachine.current}},{key:Symbol.toStringTag,get:function(){return"[Task "+this.id+"]"}}]),r}(t.EventEmitter);function k(){var t=new j(void 0,{ignoreChildErrors:!0});return t.start(),t}var T={root:k(),reset:function(){try{return Promise.resolve(T.root.halt()).then((function(){T.root=k()}))}catch(t){return Promise.reject(t)}},halt:function(){try{return Promise.resolve(T.root.halt()).then((function(){}))}catch(t){return Promise.reject(t)}}};exports.Deferred=h,exports.Effection=T,exports.Task=j,exports.deprecated=function(t,r){return function(){try{throw new Error("trace")}catch(r){var e=r.stack.split("\n").slice(3,4),n=e[0];console.warn(t,"\n"+n)}for(var i=arguments.length,o=new Array(i),s=0;s<i;s++)o[s]=arguments[s];return r.call.apply(r,[this].concat(o))}},exports.run=function(t,r){return T.root.spawn(t,r)},exports.sleep=function(t){return function(r){return function(e){var n=setTimeout(e,t);r.ensure((function(){return clearTimeout(n)}))}}};
 //# sourceMappingURL=core.cjs.production.min.js.map

dist/core.esm.js

@@ -226,2 +226,4 @@ import { EventEmitter } from 'events';
     this.didHalt = false;
+    this.didEnter = false;
+    this.continuations = [];
   } // make this an async function to delay the first iteration until the next event loop tick
@@ -244,5 +246,27 @@
     }
+  } // the purpose of this method is solely to make `step` reentrant, that is we
+  // should be able to handle a `halt` which occurs while we are already in a
+  // generator. This is a rare case and should only happen under some edge
+  // cases, for example a task halting itself, or a task causing one of its
+  // siblings to fail.
+  ;
+
+  _proto.resume = function resume(iter) {
+    this.continuations.push(iter); // only enter this loop if we aren't already running it
+
+    if (!this.didEnter) {
+      this.didEnter = true; // acquire lock
+      // use while loop since collection can be modified during iteration
+
+      var continuation;
+
+      while (continuation = this.continuations.shift()) {
+        this.step(continuation);
+      }
+
+      this.didEnter = false; // release lock
+    }
   };
 
-  _proto.resume = function resume(iter) {
+  _proto.step = function step(iter) {
     var next;
@@ -692,2 +716,9 @@
     }
+  },
+  halt: function halt() {
+    try {
+      return Promise.resolve(Effection.root.halt()).then(function () {});
+    } catch (e) {
+      return Promise.reject(e);
+    }
   }
@@ -701,5 +732,3 @@ };
       task.ensure(function () {
-        if (timeoutId) {
-          clearTimeout(timeoutId);
-        }
+        return clearTimeout(timeoutId);
       });
@@ -706,0 +735,0 @@ };

dist/effection.d.ts

@@ -5,2 +5,3 @@ import { Task } from './task';
     reset(): Promise<void>;
+    halt(): Promise<void>;
 };

package.json

 {
   "name": "@effection/core",
-  "version": "2.0.0-preview.2-ed0bed9",
+  "version": "2.0.0-preview.3-2febf01",
   "main": "dist/index.js",
@@ -23,3 +23,3 @@ "types": "dist/index.d.ts",
     "expect": "^25.3.0",
-    "mocha": "^7.1.1",
+    "mocha": "^8.3.1",
     "ts-node": "^8.8.2",
@@ -26,0 +26,0 @@ "tsdx": "0.13.2",

src/controller/iterator-controller.ts

@@ -8,6 +8,11 @@ import { Controller } from './controller';
 
+type Continuation = () => IteratorResult<Operation<unknown>>;
+
 export class IteratorController<TOut> implements Controller<TOut>, Trapper {
   private didHalt = false;
+  private didEnter = false;
   private subTask?: Task;
 
+  private continuations: Continuation[] = [];
+
   constructor(private controls: Controls<TOut>, private iterator: OperationIterator<TOut>) {
@@ -21,3 +26,22 @@ }
 
-  resume(iter: () => IteratorResult<Operation<unknown>>) {
+  // the purpose of this method is solely to make `step` reentrant, that is we
+  // should be able to handle a `halt` which occurs while we are already in a
+  // generator. This is a rare case and should only happen under some edge
+  // cases, for example a task halting itself, or a task causing one of its
+  // siblings to fail.
+  resume(iter: Continuation) {
+    this.continuations.push(iter);
+    // only enter this loop if we aren't already running it
+    if(!this.didEnter) {
+      this.didEnter = true; // acquire lock
+      // use while loop since collection can be modified during iteration
+      let continuation;
+      while(continuation = this.continuations.shift()) {
+        this.step(continuation);
+      }
+      this.didEnter = false; // release lock
+    }
+  }
+
+  step(iter: Continuation) {
     let next;
@@ -24,0 +48,0 @@ try {

src/effection.ts

@@ -15,3 +15,7 @@ import { Task } from './task';
     Effection.root = createRootTask();
+  },
+
+  async halt() {
+    await Effection.root.halt();
   }
 }

src/sleep.ts

@@ -6,8 +6,4 @@ import { Operation } from './operation';
     let timeoutId = setTimeout(resolve, duration);
-    task.ensure(() => {
-      if(timeoutId) {
-        clearTimeout(timeoutId);
-      }
-    });
+    task.ensure(() => clearTimeout(timeoutId));
   }
 }

No alert changes

Improved metrics

Total package byte prevSize

155273

increased by5.1%

Lines of code

1950

increased by4%

No dependency changes