MCAP is a modular container format and logging library for pub/sub messages with arbitrary message serialization. It is primarily intended for use in robotics applications, and works well under various workloads, resource constraints, and durability requirements.
The @mcap/nodejs package provides utilities for working with MCAP files from Node.js.
import { loadDecompressHandlers } from "@mcap/support";
import { FileHandleReadable } from "@mcap/nodejs";
import { McapIndexedReader } from "@mcap/core";
import { open } from "fs/promises";
const decompressHandlers = await loadDecompressHandlers();
const fileHandle = await open("file.mcap", "r");
const reader = await McapIndexedReader.Initialize({
readable: new FileHandleReadable(fileHandle),
decompressHandlers,
});
import zstd from "@foxglove/wasm-zstd";
import { FileHandleWritable } from "@mcap/nodejs";
import { McapWriter } from "@mcap/core";
import { open } from "fs/promises";
await zstd.isLoaded;
const fileHandle = await open("file.mcap", "wx");
const writer = new McapWriter({
writable: new FileHandleWritable(fileHandle),
compressChunk: (data) => ({
compression: "zstd",
compressedData: zstd.compress(data),
}),
});
@mcap/nodejs is licensed under the MIT License.
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