@tldraw/state/dist-esm/lib/transactions.mjs.map

tldraw infinite canvas SDK (state).

{
  "version": 3,
  "sources": ["../../src/lib/transactions.ts"],
  "sourcesContent": ["import { _Atom } from './Atom'\nimport { EffectScheduler } from './EffectScheduler'\nimport { GLOBAL_START_EPOCH } from './constants'\nimport { singleton } from './helpers'\nimport { Child, Signal } from './types'\n\nclass Transaction {\n\tasyncProcessCount = 0\n\tconstructor(\n\t\tpublic readonly parent: Transaction | null,\n\t\tpublic readonly isSync: boolean\n\t) {}\n\n\tinitialAtomValues = new Map<_Atom, any>()\n\n\t/**\n\t * Get whether this transaction is a root (no parents).\n\t *\n\t * @public\n\t */\n\t// eslint-disable-next-line no-restricted-syntax\n\tget isRoot() {\n\t\treturn this.parent === null\n\t}\n\n\t/**\n\t * Commit the transaction's changes.\n\t *\n\t * @public\n\t */\n\tcommit() {\n\t\tif (inst.globalIsReacting) {\n\t\t\t// if we're committing during a reaction we actually need to\n\t\t\t// use the 'cleanup' reactors set to ensure we re-run effects if necessary\n\t\t\tfor (const atom of this.initialAtomValues.keys()) {\n\t\t\t\ttraverseAtomForCleanup(atom)\n\t\t\t}\n\t\t} else if (this.isRoot) {\n\t\t\t// For root transactions, flush changed atoms\n\t\t\tflushChanges(this.initialAtomValues.keys())\n\t\t} else {\n\t\t\t// For transactions with parents, add the transaction's initial values to the parent's.\n\t\t\tthis.initialAtomValues.forEach((value, atom) => {\n\t\t\t\tif (!this.parent!.initialAtomValues.has(atom)) {\n\t\t\t\t\tthis.parent!.initialAtomValues.set(atom, value)\n\t\t\t\t}\n\t\t\t})\n\t\t}\n\t}\n\n\t/**\n\t * Abort the transaction.\n\t *\n\t * @public\n\t */\n\tabort() {\n\t\tinst.globalEpoch++\n\n\t\t// Reset each of the transaction's atoms to its initial value.\n\t\tthis.initialAtomValues.forEach((value, atom) => {\n\t\t\tatom.set(value)\n\t\t\tatom.historyBuffer?.clear()\n\t\t})\n\n\t\t// Commit the changes.\n\t\tthis.commit()\n\t}\n}\n\nconst inst = singleton('transactions', () => ({\n\t// The current epoch (global to all atoms).\n\tglobalEpoch: GLOBAL_START_EPOCH + 1,\n\t// Whether any transaction is reacting.\n\tglobalIsReacting: false,\n\tcurrentTransaction: null as Transaction | null,\n\n\tcleanupReactors: null as null | Set<EffectScheduler<unknown>>,\n\treactionEpoch: GLOBAL_START_EPOCH + 1,\n}))\n\n/**\n * Gets the current reaction epoch, which is used to track when reactions are running.\n * The reaction epoch is updated at the start of each reaction cycle.\n *\n * @returns The current reaction epoch number\n * @public\n */\nexport function getReactionEpoch() {\n\treturn inst.reactionEpoch\n}\n\n/**\n * Gets the current global epoch, which is incremented every time any atom changes.\n * This is used to track changes across the entire reactive system.\n *\n * @returns The current global epoch number\n * @public\n */\nexport function getGlobalEpoch() {\n\treturn inst.globalEpoch\n}\n\n/**\n * Checks whether any reactions are currently executing.\n * When true, the system is in the middle of processing effects and side effects.\n *\n * @returns True if reactions are currently running, false otherwise\n * @public\n */\nexport function getIsReacting() {\n\treturn inst.globalIsReacting\n}\n\nfunction traverse(reactors: Set<EffectScheduler<unknown>>, child: Child) {\n\tif (child.lastTraversedEpoch === inst.globalEpoch) {\n\t\treturn\n\t}\n\n\tchild.lastTraversedEpoch = inst.globalEpoch\n\n\tif (child instanceof EffectScheduler) {\n\t\treactors.add(child)\n\t} else {\n\t\t;(child as any as Signal<any>).children.visit((c) => traverse(reactors, c))\n\t}\n}\n\n/**\n * Collect all of the reactors that need to run for an atom and run them.\n *\n * @param atoms - The atoms to flush changes for.\n */\nfunction flushChanges(atoms: Iterable<_Atom>) {\n\tif (inst.globalIsReacting) {\n\t\tthrow new Error('flushChanges cannot be called during a reaction')\n\t}\n\n\tconst outerTxn = inst.currentTransaction\n\ttry {\n\t\t// clear the transaction stack\n\t\tinst.currentTransaction = null\n\t\tinst.globalIsReacting = true\n\t\tinst.reactionEpoch = inst.globalEpoch\n\n\t\t// Collect all of the visited reactors.\n\t\tconst reactors = new Set<EffectScheduler<unknown>>()\n\n\t\tfor (const atom of atoms) {\n\t\t\tatom.children.visit((child) => traverse(reactors, child))\n\t\t}\n\n\t\t// Run each reactor.\n\t\tfor (const r of reactors) {\n\t\t\tr.maybeScheduleEffect()\n\t\t}\n\n\t\tlet updateDepth = 0\n\t\twhile (inst.cleanupReactors?.size) {\n\t\t\tif (updateDepth++ > 1000) {\n\t\t\t\tthrow new Error('Reaction update depth limit exceeded')\n\t\t\t}\n\t\t\tconst reactors = inst.cleanupReactors\n\t\t\tinst.cleanupReactors = null\n\t\t\tfor (const r of reactors) {\n\t\t\t\tr.maybeScheduleEffect()\n\t\t\t}\n\t\t}\n\t} finally {\n\t\tinst.cleanupReactors = null\n\t\tinst.globalIsReacting = false\n\t\tinst.currentTransaction = outerTxn\n\t}\n}\n\n/**\n * Handle a change to an atom.\n *\n * @param atom The atom that changed.\n * @param previousValue The atom's previous value.\n *\n * @internal\n */\nexport function atomDidChange(atom: _Atom, previousValue: any) {\n\tif (inst.currentTransaction) {\n\t\t// If we are in a transaction, then all we have to do is preserve\n\t\t// the value of the atom at the start of the transaction in case\n\t\t// we need to roll back.\n\t\tif (!inst.currentTransaction.initialAtomValues.has(atom)) {\n\t\t\tinst.currentTransaction.initialAtomValues.set(atom, previousValue)\n\t\t}\n\t} else if (inst.globalIsReacting) {\n\t\t// If the atom changed during the reaction phase of flushChanges\n\t\t// (and there are no transactions started inside the reaction phase)\n\t\t// then we are past the point where a transaction can be aborted\n\t\t// so we don't need to note down the previousValue.\n\t\ttraverseAtomForCleanup(atom)\n\t} else {\n\t\t// If there is no transaction, flush the changes immediately.\n\t\tflushChanges([atom])\n\t}\n}\n\nfunction traverseAtomForCleanup(atom: _Atom) {\n\tconst rs = (inst.cleanupReactors ??= new Set())\n\tatom.children.visit((child) => traverse(rs, child))\n}\n\n/**\n * Advances the global epoch counter by one.\n * This is used internally to track when changes occur across the reactive system.\n *\n * @internal\n */\nexport function advanceGlobalEpoch() {\n\tinst.globalEpoch++\n}\n\n/**\n * Batches state updates, deferring side effects until after the transaction completes.\n * Unlike {@link transact}, this function always creates a new transaction, allowing for nested transactions.\n *\n * @example\n * ```ts\n * const firstName = atom('firstName', 'John')\n * const lastName = atom('lastName', 'Doe')\n *\n * react('greet', () => {\n *   console.log(`Hello, ${firstName.get()} ${lastName.get()}!`)\n * })\n *\n * // Logs \"Hello, John Doe!\"\n *\n * transaction(() => {\n *  firstName.set('Jane')\n *  lastName.set('Smith')\n * })\n *\n * // Logs \"Hello, Jane Smith!\"\n * ```\n *\n * If the function throws, the transaction is aborted and any signals that were updated during the transaction revert to their state before the transaction began.\n *\n * @example\n * ```ts\n * const firstName = atom('firstName', 'John')\n * const lastName = atom('lastName', 'Doe')\n *\n * react('greet', () => {\n *   console.log(`Hello, ${firstName.get()} ${lastName.get()}!`)\n * })\n *\n * // Logs \"Hello, John Doe!\"\n *\n * transaction(() => {\n *  firstName.set('Jane')\n *  throw new Error('oops')\n * })\n *\n * // Does not log\n * // firstName.get() === 'John'\n * ```\n *\n * A `rollback` callback is passed into the function.\n * Calling this will prevent the transaction from committing and will revert any signals that were updated during the transaction to their state before the transaction began.\n *\n * @example\n * ```ts\n * const firstName = atom('firstName', 'John')\n * const lastName = atom('lastName', 'Doe')\n *\n * react('greet', () => {\n *   console.log(`Hello, ${firstName.get()} ${lastName.get()}!`)\n * })\n *\n * // Logs \"Hello, John Doe!\"\n *\n * transaction((rollback) => {\n *  firstName.set('Jane')\n *  lastName.set('Smith')\n *  rollback()\n * })\n *\n * // Does not log\n * // firstName.get() === 'John'\n * // lastName.get() === 'Doe'\n * ```\n *\n * @param fn - The function to run in a transaction, called with a function to roll back the change.\n * @returns The return value of the function\n * @public\n */\nexport function transaction<T>(fn: (rollback: () => void) => T) {\n\tconst txn = new Transaction(inst.currentTransaction, true)\n\n\t// Set the current transaction to the transaction\n\tinst.currentTransaction = txn\n\n\ttry {\n\t\tlet result = undefined as T | undefined\n\t\tlet rollback = false\n\n\t\ttry {\n\t\t\t// Run the function.\n\t\t\tresult = fn(() => (rollback = true))\n\t\t} catch (e) {\n\t\t\t// Abort the transaction if the function throws.\n\t\t\ttxn.abort()\n\t\t\tthrow e\n\t\t}\n\n\t\tif (inst.currentTransaction !== txn) {\n\t\t\tthrow new Error('Transaction boundaries overlap')\n\t\t}\n\n\t\tif (rollback) {\n\t\t\t// If the rollback was triggered, abort the transaction.\n\t\t\ttxn.abort()\n\t\t} else {\n\t\t\ttxn.commit()\n\t\t}\n\n\t\treturn result\n\t} finally {\n\t\t// Set the current transaction to the transaction's parent.\n\t\tinst.currentTransaction = txn.parent\n\t}\n}\n\n/**\n * Like {@link transaction}, but does not create a new transaction if there is already one in progress.\n * This is the preferred way to batch state updates when you don't need the rollback functionality.\n *\n * @example\n * ```ts\n * const count = atom('count', 0)\n * const doubled = atom('doubled', 0)\n *\n * react('update doubled', () => {\n *   console.log(`Count: ${count.get()}, Doubled: ${doubled.get()}`)\n * })\n *\n * // This batches both updates into a single reaction\n * transact(() => {\n *   count.set(5)\n *   doubled.set(count.get() * 2)\n * })\n * // Logs: \"Count: 5, Doubled: 10\"\n * ```\n *\n * @param fn - The function to run in a transaction\n * @returns The return value of the function\n * @public\n */\nexport function transact<T>(fn: () => T): T {\n\tif (inst.currentTransaction) {\n\t\treturn fn()\n\t}\n\treturn transaction(fn)\n}\n\n/**\n * Defers the execution of asynchronous effects until they can be properly handled.\n * This function creates an asynchronous transaction context that batches state updates\n * across async operations while preventing conflicts with synchronous transactions.\n *\n * @example\n * ```ts\n * const data = atom('data', null)\n * const loading = atom('loading', false)\n *\n * await deferAsyncEffects(async () => {\n *   loading.set(true)\n *   const result = await fetch('/api/data')\n *   const json = await result.json()\n *   data.set(json)\n *   loading.set(false)\n * })\n * ```\n *\n * @param fn - The async function to execute within the deferred context\n * @returns A promise that resolves to the return value of the function\n * @throws Will throw if called during a synchronous transaction\n * @internal\n */\nexport async function deferAsyncEffects<T>(fn: () => Promise<T>) {\n\t// Can't kick off async transactions during a sync transaction because\n\t// the async transaction won't finish until after the sync transaction\n\t// is done.\n\tif (inst.currentTransaction?.isSync) {\n\t\tthrow new Error('deferAsyncEffects cannot be called during a sync transaction')\n\t}\n\n\t// Can't kick off async transactions during a reaction phase at the moment,\n\t// because the transaction stack is cleared after the reaction phase.\n\t// So wait until the path ahead is clear\n\twhile (inst.globalIsReacting) {\n\t\tawait new Promise((r) => queueMicrotask(() => r(null)))\n\t}\n\n\tconst txn = inst.currentTransaction ?? new Transaction(null, false)\n\n\t// don't think this can happen, but just in case\n\tif (txn.isSync) throw new Error('deferAsyncEffects cannot be called during a sync transaction')\n\n\tinst.currentTransaction = txn\n\ttxn.asyncProcessCount++\n\n\tlet result = undefined as T | undefined\n\n\tlet error = undefined as any\n\ttry {\n\t\t// Run the function.\n\t\tresult = await fn()\n\t} catch (e) {\n\t\t// Abort the transaction if the function throws.\n\t\terror = e ?? null\n\t}\n\n\tif (--txn.asyncProcessCount > 0) {\n\t\tif (typeof error !== 'undefined') {\n\t\t\t// If the rollback was triggered, abort the transaction.\n\t\t\tthrow error\n\t\t} else {\n\t\t\treturn result\n\t\t}\n\t}\n\n\tinst.currentTransaction = null\n\n\tif (typeof error !== 'undefined') {\n\t\t// If the rollback was triggered, abort the transaction.\n\t\ttxn.abort()\n\t\tthrow error\n\t} else {\n\t\ttxn.commit()\n\t\treturn result\n\t}\n}\n"],
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