{
  "version": 3,
  "sources": ["../../src/Atom.ts"],
  "sourcesContent": ["import { ArraySet } from './ArraySet.js'\nimport { maybeCaptureParent } from './capture.js'\nimport { EMPTY_ARRAY, equals } from './helpers.js'\nimport { HistoryBuffer } from './HistoryBuffer.js'\nimport { advanceGlobalEpoch, atomDidChange, globalEpoch } from './transactions.js'\nimport { Child, ComputeDiff, RESET_VALUE, Signal } from './types.js'\n\n/**\n * The options to configure an atom, passed into the [[atom]] function.\n * @public\n */\nexport interface AtomOptions<Value, Diff> {\n\t/**\n\t * The maximum number of diffs to keep in the history buffer.\n\t *\n\t * If you don't need to compute diffs, or if you will supply diffs manually via [[Atom.set]], you can leave this as `undefined` and no history buffer will be created.\n\t *\n\t * If you expect the value to be part of an active effect subscription all the time, and to not change multiple times inside of a single transaction, you can set this to a relatively low number (e.g. 10).\n\t *\n\t * Otherwise, set this to a higher number based on your usage pattern and memory constraints.\n\t *\n\t */\n\thistoryLength?: number\n\t/**\n\t * A method used to compute a diff between the atom's old and new values. If provided, it will not be used unless you also specify [[AtomOptions.historyLength]].\n\t */\n\tcomputeDiff?: ComputeDiff<Value, Diff>\n\t/**\n\t * If provided, this will be used to compare the old and new values of the atom to determine if the value has changed.\n\t * By default, values are compared using first using strict equality (`===`), then `Object.is`, and finally any `.equals` method present in the object's prototype chain.\n\t * @param a\n\t * @param b\n\t * @returns\n\t */\n\tisEqual?: (a: any, b: any) => boolean\n}\n\n/**\n * An Atom is a signal that can be updated directly by calling [[Atom.set]] or [[Atom.update]].\n *\n * Atoms are created using the [[atom]] function.\n *\n * @example\n * ```ts\n * const name = atom('name', 'John')\n *\n * console.log(name.value) // 'John'\n * ```\n *\n * @public\n */\nexport interface Atom<Value, Diff = unknown> extends Signal<Value, Diff> {\n\t/**\n\t * Sets the value of this atom to the given value. If the value is the same as the current value, this is a no-op.\n\t *\n\t * @param value - The new value to set.\n\t * @param diff - The diff to use for the update. If not provided, the diff will be computed using [[AtomOptions.computeDiff]].\n\t */\n\tset(value: Value, diff?: Diff): Value\n\t/**\n\t * Updates the value of this atom using the given updater function. If the returned value is the same as the current value, this is a no-op.\n\t *\n\t * @param updater - A function that takes the current value and returns the new value.\n\t */\n\tupdate(updater: (value: Value) => Value): Value\n}\n\n/**\n * @internal\n */\nexport class _Atom<Value, Diff = unknown> implements Atom<Value, Diff> {\n\tconstructor(\n\t\tpublic readonly name: string,\n\t\tprivate current: Value,\n\t\toptions?: AtomOptions<Value, Diff>\n\t) {\n\t\tthis.isEqual = options?.isEqual ?? null\n\n\t\tif (!options) return\n\n\t\tif (options.historyLength) {\n\t\t\tthis.historyBuffer = new HistoryBuffer(options.historyLength)\n\t\t}\n\n\t\tthis.computeDiff = options.computeDiff\n\t}\n\n\treadonly isEqual: null | ((a: any, b: any) => boolean)\n\n\tcomputeDiff?: ComputeDiff<Value, Diff>\n\n\tlastChangedEpoch = globalEpoch\n\n\tchildren = new ArraySet<Child>()\n\n\thistoryBuffer?: HistoryBuffer<Diff>\n\n\t__unsafe__getWithoutCapture(): Value {\n\t\treturn this.current\n\t}\n\n\tget value() {\n\t\tmaybeCaptureParent(this)\n\t\treturn this.current\n\t}\n\n\tset(value: Value, diff?: Diff): Value {\n\t\t// If the value has not changed, do nothing.\n\t\tif (this.isEqual?.(this.current, value) ?? equals(this.current, value)) {\n\t\t\treturn this.current\n\t\t}\n\n\t\t// Tick forward the global epoch\n\t\tadvanceGlobalEpoch()\n\n\t\t// Add the diff to the history buffer.\n\t\tif (this.historyBuffer) {\n\t\t\tthis.historyBuffer.pushEntry(\n\t\t\t\tthis.lastChangedEpoch,\n\t\t\t\tglobalEpoch,\n\t\t\t\tdiff ??\n\t\t\t\t\tthis.computeDiff?.(this.current, value, this.lastChangedEpoch, globalEpoch) ??\n\t\t\t\t\tRESET_VALUE\n\t\t\t)\n\t\t}\n\n\t\t// Update the atom's record of the epoch when last changed.\n\t\tthis.lastChangedEpoch = globalEpoch\n\n\t\tconst oldValue = this.current\n\t\tthis.current = value\n\n\t\t// Notify all children that this atom has changed.\n\t\tatomDidChange(this, oldValue)\n\n\t\treturn value\n\t}\n\n\tupdate(updater: (value: Value) => Value): Value {\n\t\treturn this.set(updater(this.current))\n\t}\n\n\tgetDiffSince(epoch: number): RESET_VALUE | Diff[] {\n\t\tmaybeCaptureParent(this)\n\n\t\t// If no changes have occurred since the given epoch, return an empty array.\n\t\tif (epoch >= this.lastChangedEpoch) {\n\t\t\treturn EMPTY_ARRAY\n\t\t}\n\n\t\treturn this.historyBuffer?.getChangesSince(epoch) ?? RESET_VALUE\n\t}\n}\n\n/**\n * Creates a new [[Atom]].\n *\n * An Atom is a signal that can be updated directly by calling [[Atom.set]] or [[Atom.update]].\n *\n * @example\n * ```ts\n * const name = atom('name', 'John')\n *\n * name.value // 'John'\n *\n * name.set('Jane')\n *\n * name.value // 'Jane'\n * ```\n *\n * @public\n */\nexport function atom<Value, Diff = unknown>(\n\t/**\n\t * A name for the signal. This is used for debugging and profiling purposes, it does not need to be unique.\n\t */\n\tname: string,\n\t/**\n\t * The initial value of the signal.\n\t */\n\tinitialValue: Value,\n\t/**\n\t * The options to configure the atom. See [[AtomOptions]].\n\t */\n\toptions?: AtomOptions<Value, Diff>\n): Atom<Value, Diff> {\n\treturn new _Atom(name, initialValue, options)\n}\n\n/**\n * Returns true if the given value is an [[Atom]].\n * @public\n */\nexport function isAtom(value: unknown): value is Atom<unknown> {\n\treturn value instanceof _Atom\n}\n"],
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