FileAttachment.parquet (#374)

docs/lib/arrow.md

@@ -43,3 +43,18 @@ Or using [Inputs.table](./inputs#table):
 ```js echo
 Inputs.table(table)
 ```
+
+More commonly you might use an Apache Parquet file. We use [parquet-wasm](https://kylebarron.dev/parquet-wasm/).
+
+```js echo
+const schools = FileAttachment("schools.parquet").parquet();
+```
+
+```js echo
+Plot.plot({
+  projection: "albers-usa",
+  marks: [
+    Plot.dot(schools, {x: "LONGITUD", y: "LATITUDE"})
+  ]
+})
+```

src/client/stdlib/fileAttachment.js

@@ -68,6 +68,10 @@ class AbstractFile {
     const [Arrow, response] = await Promise.all([import("npm:apache-arrow"), remote_fetch(this)]);
     return Arrow.tableFromIPC(response);
   }
+  async parquet() {
+    const [Arrow, Parquet, buffer] = await Promise.all([import("npm:apache-arrow"), import("npm:parquet-wasm/esm/arrow1.js").then(async (Parquet) => (await Parquet.default(), Parquet)), this.arrayBuffer()]); // prettier-ignore
+    return Arrow.tableFromIPC(Parquet.readParquet(new Uint8Array(buffer)).intoIPCStream());
+  }
   async sqlite() {
     return import("observablehq:stdlib/sqlite").then((sqlite) => sqlite.SQLiteDatabaseClient.open(remote_fetch(this)));
   }

test/mocks/jsdelivr.ts

@@ -17,6 +17,7 @@ const packages: [name: string, version: string][] = [
   ["leaflet", "1.9.4"],
   ["lodash", "4.17.21"],
   ["mermaid", "10.6.1"],
+  ["parquet-wasm", "0.6.0-beta.1"],
   ["sql.js", "1.9.0"],
   ["topojson-client", "3.1.0"]
 ];