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const instanceOfAny = (object, constructors) => constructors.some((c) => object instanceof c);
let idbProxyableTypes;
let cursorAdvanceMethods;
// This is a function to prevent it throwing up in node environments.
function getIdbProxyableTypes() {
return (idbProxyableTypes ||
(idbProxyableTypes = [
IDBDatabase,
IDBObjectStore,
IDBIndex,
IDBCursor,
IDBTransaction,
]));
}
// This is a function to prevent it throwing up in node environments.
function getCursorAdvanceMethods() {
return (cursorAdvanceMethods ||
(cursorAdvanceMethods = [
IDBCursor.prototype.advance,
IDBCursor.prototype.continue,
IDBCursor.prototype.continuePrimaryKey,
]));
}
const cursorRequestMap = new WeakMap();
const transactionDoneMap = new WeakMap();
const transactionStoreNamesMap = new WeakMap();
const transformCache = new WeakMap();
const reverseTransformCache = new WeakMap();
function promisifyRequest(request) {
const promise = new Promise((resolve, reject) => {
const unlisten = () => {
request.removeEventListener('success', success);
request.removeEventListener('error', error);
};
const success = () => {
resolve(wrap(request.result));
unlisten();
};
const error = () => {
reject(request.error);
unlisten();
};
request.addEventListener('success', success);
request.addEventListener('error', error);
});
promise
.then((value) => {
// Since cursoring reuses the IDBRequest (*sigh*), we cache it for later retrieval
// (see wrapFunction).
if (value instanceof IDBCursor) {
cursorRequestMap.set(value, request);
}
// Catching to avoid "Uncaught Promise exceptions"
})
.catch(() => { });
// This mapping exists in reverseTransformCache but doesn't doesn't exist in transformCache. This
// is because we create many promises from a single IDBRequest.
reverseTransformCache.set(promise, request);
return promise;
}
function cacheDonePromiseForTransaction(tx) {
// Early bail if we've already created a done promise for this transaction.
if (transactionDoneMap.has(tx))
return;
const done = new Promise((resolve, reject) => {
const unlisten = () => {
tx.removeEventListener('complete', complete);
tx.removeEventListener('error', error);
tx.removeEventListener('abort', error);
};
const complete = () => {
resolve();
unlisten();
};
const error = () => {
reject(tx.error || new DOMException('AbortError', 'AbortError'));
unlisten();
};
tx.addEventListener('complete', complete);
tx.addEventListener('error', error);
tx.addEventListener('abort', error);
});
// Cache it for later retrieval.
transactionDoneMap.set(tx, done);
}
let idbProxyTraps = {
get(target, prop, receiver) {
if (target instanceof IDBTransaction) {
// Special handling for transaction.done.
if (prop === 'done')
return transactionDoneMap.get(target);
// Polyfill for objectStoreNames because of Edge.
if (prop === 'objectStoreNames') {
return target.objectStoreNames || transactionStoreNamesMap.get(target);
}
// Make tx.store return the only store in the transaction, or undefined if there are many.
if (prop === 'store') {
return receiver.objectStoreNames[1]
? undefined
: receiver.objectStore(receiver.objectStoreNames[0]);
}
}
// Else transform whatever we get back.
return wrap(target[prop]);
},
set(target, prop, value) {
target[prop] = value;
return true;
},
has(target, prop) {
if (target instanceof IDBTransaction &&
(prop === 'done' || prop === 'store')) {
return true;
}
return prop in target;
},
};
function replaceTraps(callback) {
idbProxyTraps = callback(idbProxyTraps);
}
function wrapFunction(func) {
// Due to expected object equality (which is enforced by the caching in `wrap`), we
// only create one new func per func.
// Edge doesn't support objectStoreNames (booo), so we polyfill it here.
if (func === IDBDatabase.prototype.transaction &&
!('objectStoreNames' in IDBTransaction.prototype)) {
return function (storeNames, ...args) {
const tx = func.call(unwrap(this), storeNames, ...args);
transactionStoreNamesMap.set(tx, storeNames.sort ? storeNames.sort() : [storeNames]);
return wrap(tx);
};
}
// Cursor methods are special, as the behaviour is a little more different to standard IDB. In
// IDB, you advance the cursor and wait for a new 'success' on the IDBRequest that gave you the
// cursor. It's kinda like a promise that can resolve with many values. That doesn't make sense
// with real promises, so each advance methods returns a new promise for the cursor object, or
// undefined if the end of the cursor has been reached.
if (getCursorAdvanceMethods().includes(func)) {
return function (...args) {
// Calling the original function with the proxy as 'this' causes ILLEGAL INVOCATION, so we use
// the original object.
func.apply(unwrap(this), args);
return wrap(cursorRequestMap.get(this));
};
}
return function (...args) {
// Calling the original function with the proxy as 'this' causes ILLEGAL INVOCATION, so we use
// the original object.
return wrap(func.apply(unwrap(this), args));
};
}
function transformCachableValue(value) {
if (typeof value === 'function')
return wrapFunction(value);
// This doesn't return, it just creates a 'done' promise for the transaction,
// which is later returned for transaction.done (see idbObjectHandler).
if (value instanceof IDBTransaction)
cacheDonePromiseForTransaction(value);
if (instanceOfAny(value, getIdbProxyableTypes()))
return new Proxy(value, idbProxyTraps);
// Return the same value back if we're not going to transform it.
return value;
}
function wrap(value) {
// We sometimes generate multiple promises from a single IDBRequest (eg when cursoring), because
// IDB is weird and a single IDBRequest can yield many responses, so these can't be cached.
if (value instanceof IDBRequest)
return promisifyRequest(value);
// If we've already transformed this value before, reuse the transformed value.
// This is faster, but it also provides object equality.
if (transformCache.has(value))
return transformCache.get(value);
const newValue = transformCachableValue(value);
// Not all types are transformed.
// These may be primitive types, so they can't be WeakMap keys.
if (newValue !== value) {
transformCache.set(value, newValue);
reverseTransformCache.set(newValue, value);
}
return newValue;
}
const unwrap = (value) => reverseTransformCache.get(value);
export { reverseTransformCache as a, instanceOfAny as i, replaceTraps as r, unwrap as u, wrap as w };
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