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- // Public interface
- var S = function S(fn, value) {
- var node = new ComputationNode(fn, value);
- return function computation() {
- return node.current();
- };
- };
- // compatibility with commonjs systems that expect default export to be at require('s.js').default rather than just require('s-js')
- Object.defineProperty(S, 'default', { value: S });
- export default S;
- S.root = function root(fn) {
- var owner = Owner, root = fn.length === 0 ? UNOWNED : new ComputationNode(null, null), result = undefined, disposer = fn.length === 0 ? null : function _dispose() {
- if (RunningClock !== null) {
- RootClock.disposes.add(root);
- }
- else {
- dispose(root);
- }
- };
- Owner = root;
- if (RunningClock === null) {
- result = topLevelRoot(fn, disposer, owner);
- }
- else {
- result = disposer === null ? fn() : fn(disposer);
- Owner = owner;
- }
- return result;
- };
- function topLevelRoot(fn, disposer, owner) {
- try {
- return disposer === null ? fn() : fn(disposer);
- }
- finally {
- Owner = owner;
- }
- }
- S.on = function on(ev, fn, seed, onchanges) {
- if (Array.isArray(ev))
- ev = callAll(ev);
- onchanges = !!onchanges;
- return S(on, seed);
- function on(value) {
- var running = RunningNode;
- ev();
- if (onchanges)
- onchanges = false;
- else {
- RunningNode = null;
- value = fn(value);
- RunningNode = running;
- }
- return value;
- }
- };
- function callAll(ss) {
- return function all() {
- for (var i = 0; i < ss.length; i++)
- ss[i]();
- };
- }
- S.effect = function effect(fn, value) {
- new ComputationNode(fn, value);
- };
- S.data = function data(value) {
- var node = new DataNode(value);
- return function data(value) {
- if (arguments.length === 0) {
- return node.current();
- }
- else {
- return node.next(value);
- }
- };
- };
- S.value = function value(current, eq) {
- var data = S.data(current), age = -1;
- return function value(update) {
- if (arguments.length === 0) {
- return data();
- }
- else {
- var same = eq ? eq(current, update) : current === update;
- if (!same) {
- var time = RootClock.time;
- if (age === time)
- throw new Error("conflicting values: " + update + " is not the same as " + current);
- age = time;
- current = update;
- data(update);
- }
- return update;
- }
- };
- };
- S.freeze = function freeze(fn) {
- var result = undefined;
- if (RunningClock !== null) {
- result = fn();
- }
- else {
- RunningClock = RootClock;
- RunningClock.changes.reset();
- try {
- result = fn();
- event();
- }
- finally {
- RunningClock = null;
- }
- }
- return result;
- };
- S.sample = function sample(fn) {
- var result, running = RunningNode;
- if (running !== null) {
- RunningNode = null;
- result = fn();
- RunningNode = running;
- }
- else {
- result = fn();
- }
- return result;
- };
- S.cleanup = function cleanup(fn) {
- if (Owner !== null) {
- if (Owner.cleanups === null)
- Owner.cleanups = [fn];
- else
- Owner.cleanups.push(fn);
- }
- else {
- console.warn("cleanups created without a root or parent will never be run");
- }
- };
- // experimental : exposing node constructors and some state
- S.makeDataNode = function makeDataNode(value) {
- return new DataNode(value);
- };
- S.makeComputationNode = function makeComputationNode(fn, seed) {
- return new ComputationNode(fn, seed);
- };
- S.isFrozen = function isFrozen() {
- return RunningClock !== null;
- };
- S.isListening = function isListening() {
- return RunningNode !== null;
- };
- // Internal implementation
- /// Graph classes and operations
- var Clock = /** @class */ (function () {
- function Clock() {
- this.time = 0;
- this.changes = new Queue(); // batched changes to data nodes
- this.updates = new Queue(); // computations to update
- this.disposes = new Queue(); // disposals to run after current batch of updates finishes
- }
- return Clock;
- }());
- var RootClockProxy = {
- time: function () { return RootClock.time; }
- };
- var DataNode = /** @class */ (function () {
- function DataNode(value) {
- this.value = value;
- this.pending = NOTPENDING;
- this.log = null;
- }
- DataNode.prototype.current = function () {
- if (RunningNode !== null) {
- logDataRead(this, RunningNode);
- }
- return this.value;
- };
- DataNode.prototype.next = function (value) {
- if (RunningClock !== null) {
- if (this.pending !== NOTPENDING) { // value has already been set once, check for conflicts
- if (value !== this.pending) {
- throw new Error("conflicting changes: " + value + " !== " + this.pending);
- }
- }
- else { // add to list of changes
- this.pending = value;
- RootClock.changes.add(this);
- }
- }
- else { // not batching, respond to change now
- if (this.log !== null) {
- this.pending = value;
- RootClock.changes.add(this);
- event();
- }
- else {
- this.value = value;
- }
- }
- return value;
- };
- DataNode.prototype.clock = function () {
- return RootClockProxy;
- };
- return DataNode;
- }());
- var ComputationNode = /** @class */ (function () {
- function ComputationNode(fn, value) {
- this.state = CURRENT;
- this.source1 = null;
- this.source1slot = 0;
- this.sources = null;
- this.sourceslots = null;
- this.log = null;
- this.owned = null;
- this.cleanups = null;
- this.fn = fn;
- this.value = value;
- this.age = RootClock.time;
- if (fn === null)
- return;
- var owner = Owner, running = RunningNode;
- if (owner === null)
- console.warn("computations created without a root or parent will never be disposed");
- Owner = RunningNode = this;
- if (RunningClock === null) {
- toplevelComputation(this);
- }
- else {
- this.value = this.fn(this.value);
- }
- if (owner && owner !== UNOWNED) {
- if (owner.owned === null)
- owner.owned = [this];
- else
- owner.owned.push(this);
- }
- Owner = owner;
- RunningNode = running;
- }
- ComputationNode.prototype.current = function () {
- if (RunningNode !== null) {
- if (this.age === RootClock.time) {
- if (this.state === RUNNING)
- throw new Error("circular dependency");
- else
- updateNode(this); // checks for state === STALE internally, so don't need to check here
- }
- logComputationRead(this, RunningNode);
- }
- return this.value;
- };
- ComputationNode.prototype.clock = function () {
- return RootClockProxy;
- };
- return ComputationNode;
- }());
- var Log = /** @class */ (function () {
- function Log() {
- this.node1 = null;
- this.node1slot = 0;
- this.nodes = null;
- this.nodeslots = null;
- }
- return Log;
- }());
- var Queue = /** @class */ (function () {
- function Queue() {
- this.items = [];
- this.count = 0;
- }
- Queue.prototype.reset = function () {
- this.count = 0;
- };
- Queue.prototype.add = function (item) {
- this.items[this.count++] = item;
- };
- Queue.prototype.run = function (fn) {
- var items = this.items;
- for (var i = 0; i < this.count; i++) {
- fn(items[i]);
- items[i] = null;
- }
- this.count = 0;
- };
- return Queue;
- }());
- // Constants
- var NOTPENDING = {}, CURRENT = 0, STALE = 1, RUNNING = 2;
- // "Globals" used to keep track of current system state
- var RootClock = new Clock(), RunningClock = null, // currently running clock
- RunningNode = null, // currently running computation
- Owner = null, // owner for new computations
- UNOWNED = new ComputationNode(null, null);
- // Functions
- function logRead(from, to) {
- var fromslot, toslot = to.source1 === null ? -1 : to.sources === null ? 0 : to.sources.length;
- if (from.node1 === null) {
- from.node1 = to;
- from.node1slot = toslot;
- fromslot = -1;
- }
- else if (from.nodes === null) {
- from.nodes = [to];
- from.nodeslots = [toslot];
- fromslot = 0;
- }
- else {
- fromslot = from.nodes.length;
- from.nodes.push(to);
- from.nodeslots.push(toslot);
- }
- if (to.source1 === null) {
- to.source1 = from;
- to.source1slot = fromslot;
- }
- else if (to.sources === null) {
- to.sources = [from];
- to.sourceslots = [fromslot];
- }
- else {
- to.sources.push(from);
- to.sourceslots.push(fromslot);
- }
- }
- function logDataRead(data, to) {
- if (data.log === null)
- data.log = new Log();
- logRead(data.log, to);
- }
- function logComputationRead(node, to) {
- if (node.log === null)
- node.log = new Log();
- logRead(node.log, to);
- }
- function event() {
- // b/c we might be under a top level S.root(), have to preserve current root
- var owner = Owner;
- RootClock.updates.reset();
- RootClock.time++;
- try {
- run(RootClock);
- }
- finally {
- RunningClock = RunningNode = null;
- Owner = owner;
- }
- }
- function toplevelComputation(node) {
- RunningClock = RootClock;
- RootClock.changes.reset();
- RootClock.updates.reset();
- try {
- node.value = node.fn(node.value);
- if (RootClock.changes.count > 0 || RootClock.updates.count > 0) {
- RootClock.time++;
- run(RootClock);
- }
- }
- finally {
- RunningClock = Owner = RunningNode = null;
- }
- }
- function run(clock) {
- var running = RunningClock, count = 0;
- RunningClock = clock;
- clock.disposes.reset();
- // for each batch ...
- while (clock.changes.count !== 0 || clock.updates.count !== 0 || clock.disposes.count !== 0) {
- if (count > 0) // don't tick on first run, or else we expire already scheduled updates
- clock.time++;
- clock.changes.run(applyDataChange);
- clock.updates.run(updateNode);
- clock.disposes.run(dispose);
- // if there are still changes after excessive batches, assume runaway
- if (count++ > 1e5) {
- throw new Error("Runaway clock detected");
- }
- }
- RunningClock = running;
- }
- function applyDataChange(data) {
- data.value = data.pending;
- data.pending = NOTPENDING;
- if (data.log)
- markComputationsStale(data.log);
- }
- function markComputationsStale(log) {
- var node1 = log.node1, nodes = log.nodes;
- // mark all downstream nodes stale which haven't been already
- if (node1 !== null)
- markNodeStale(node1);
- if (nodes !== null) {
- for (var i = 0, len = nodes.length; i < len; i++) {
- markNodeStale(nodes[i]);
- }
- }
- }
- function markNodeStale(node) {
- var time = RootClock.time;
- if (node.age < time) {
- node.age = time;
- node.state = STALE;
- RootClock.updates.add(node);
- if (node.owned !== null)
- markOwnedNodesForDisposal(node.owned);
- if (node.log !== null)
- markComputationsStale(node.log);
- }
- }
- function markOwnedNodesForDisposal(owned) {
- for (var i = 0; i < owned.length; i++) {
- var child = owned[i];
- child.age = RootClock.time;
- child.state = CURRENT;
- if (child.owned !== null)
- markOwnedNodesForDisposal(child.owned);
- }
- }
- function updateNode(node) {
- if (node.state === STALE) {
- var owner = Owner, running = RunningNode;
- Owner = RunningNode = node;
- node.state = RUNNING;
- cleanup(node, false);
- node.value = node.fn(node.value);
- node.state = CURRENT;
- Owner = owner;
- RunningNode = running;
- }
- }
- function cleanup(node, final) {
- var source1 = node.source1, sources = node.sources, sourceslots = node.sourceslots, cleanups = node.cleanups, owned = node.owned, i, len;
- if (cleanups !== null) {
- for (i = 0; i < cleanups.length; i++) {
- cleanups[i](final);
- }
- node.cleanups = null;
- }
- if (owned !== null) {
- for (i = 0; i < owned.length; i++) {
- dispose(owned[i]);
- }
- node.owned = null;
- }
- if (source1 !== null) {
- cleanupSource(source1, node.source1slot);
- node.source1 = null;
- }
- if (sources !== null) {
- for (i = 0, len = sources.length; i < len; i++) {
- cleanupSource(sources.pop(), sourceslots.pop());
- }
- }
- }
- function cleanupSource(source, slot) {
- var nodes = source.nodes, nodeslots = source.nodeslots, last, lastslot;
- if (slot === -1) {
- source.node1 = null;
- }
- else {
- last = nodes.pop();
- lastslot = nodeslots.pop();
- if (slot !== nodes.length) {
- nodes[slot] = last;
- nodeslots[slot] = lastslot;
- if (lastslot === -1) {
- last.source1slot = slot;
- }
- else {
- last.sourceslots[lastslot] = slot;
- }
- }
- }
- }
- function dispose(node) {
- node.fn = null;
- node.log = null;
- cleanup(node, true);
- }
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