feat: add storage queries

docs/pages/typed/queries.md

@@ -0,0 +1,66 @@
+# Storage queries
+
+For `query` we have mainly two different situations. There're two kinds of storage entries: entries with and without keys.
+
+## Entries without keys
+
+For example, `System.Number` query (it returns the block number) has no keys to index it with. Therefore, under `typedApi.System.Number` we have the following structure:
+
+```ts
+type CallOptions = Partial<{
+  at: string
+  signal: AbortSignal
+}>
+
+type StorageEntryWithoutKeys<Payload> = {
+  isCompatible: IsCompatible
+  getValue: (options?: CallOptions) => Promise<Payload>
+  watchValue: (bestOrFinalized?: "best" | "finalized") => Observable<Payload>
+}
+```
+
+As you might expect, `getValue` returns you the `Payload` for that particular query, allowing you to choose which block to query (`at` can be a blockHash, `"finalized"` (the default), or `"best"`).
+
+On the other hand, `watchValue` function returns an Observable allows you to check the changes of a particular storage entry in `"best"` or `"finalized"` (the default) block.
+
+## Entries with keys
+
+Similarely, we'll use the example of `System.Account` query (it returns the information of a particular `Account`). In this case, this storage query has a key to index it with, and therefore we find the following structure:
+
+```ts
+type StorageEntryWithKeys<Args, Payload> = {
+  isCompatible: IsCompatible
+  getValue: (...args: [...Args, options?: CallOptions]) => Promise<Payload>
+  watchValue: (
+    ...args: [...Args, bestOrFinalized?: "best" | "finalized"]
+  ) => Observable<Payload>
+  getValues: (
+    keys: Array<[...Args]>,
+    options?: CallOptions,
+  ) => Promise<Array<Payload>>
+  getEntries: (
+    ...args: [PossibleParents<Args>, options?: CallOptions]
+  ) => Promise<
+    Array<{
+      keyArgs: Args
+      value: NonNullable<Payload>
+    }>
+  >
+}
+```
+
+Both `getValue` and `watchValue` have the same behaviour as in the previous case, but they require you to pass all keys required for that storage query (in our example, an address). The same function arguments that are found in the no-keys situation can be passed at the end of the call to modify which block to query, etc. For example, a query with 3 args:
+
+```ts
+typedApi.query.Pallet.Query.getValue(arg1, arg2, arg3, { at: "best" })
+```
+
+`getValues`, instead, allows you to pass several keys (addresses in this case) to get a bunch of entries at the same time.
+
+`getEntries` allows you to get all entries without passing the keys. It has also the option to pass a subset of them. For example, imagine a query with 3 keys. You would have three options to call it:
+
+```ts
+typedApi.query.Pallet.Query.getEntries({ at: "best" }) // no keys
+typedApi.query.Pallet.Query.getEntries(arg1, { at: "finalized" }) // 1/3 keys
+typedApi.query.Pallet.Query.getEntries(arg1, arg2, { at: "0x12345678" }) // 2/3 keys
+```