# @holochain-open-dev/utils > Common utilities to build Holochain web applications Latest version **0.701.0** (published 2026-10-16) · 0 weekly downloads ## Install ```sh npm install @holochain-open-dev/utils pnpm add @holochain-open-dev/utils yarn add @holochain-open-dev/utils bun add @holochain-open-dev/utils ``` ## Health **Score 70/100 (B)** — status: active. Positive: has types; esm support; no vulnerabilities; has provenance; recently updated; high maintenance score. Warnings: low downloads; pre 1.0. ## Facts | | | |---|---| | Version | 0.701.0 | | Published | 2026-10-16 | | First published | 2022-03-02 | | Weekly downloads | 0 | | TypeScript types | bundled | | Module format | ESM + CommonJS | | Dependencies | 6 | | Unpacked size | 102.1 KB | | Known vulnerabilities | 0 | | Install scripts | no | | Provenance | attested (GitHub Actions) | | GitHub stars | 7 | | Author | guillem.cordoba@gmail.com | | Maintainers | ddd-mtl, guillem.cordoba, matthme, zippy314, mattyg | ## Links - npm: https://www.npmjs.com/package/@holochain-open-dev/utils - Repository: https://github.com/holochain-open-dev/infrastructure - Homepage: https://github.com/holochain-open-dev/infrastructure#readme - Issues: https://github.com/holochain-open-dev/infrastructure/issues - npm.io page: https://npm.io/package/@holochain-open-dev/utils ## Dependencies (6) - [blakejs](https://npm.io/package/blakejs.md) ^1.2.1 - [emittery](https://npm.io/package/emittery.md) ^1.2.0 - [lodash-es](https://npm.io/package/lodash-es.md) ^4.17.21 - [sort-keys](https://npm.io/package/sort-keys.md) ^5.0.0 - [@msgpack/msgpack](https://npm.io/package/@msgpack/msgpack.md) ^3.1.3 - [@holochain/client](https://npm.io/package/@holochain/client.md) ^0.21.1 ## Recent versions - 0.701.0 (latest) — 2026-10-16 - 0.700.0-rc.0 (rc) — 2026-07-22 - 0.700.0-dev.0 (dev) — 2026-04-27 - 0.700.0 — 2026-07-31 - 0.601.2 — 2026-06-12 - 0.601.1 — 2026-05-15 - 0.601.0 — 2026-01-26 - 0.600.0 — 2025-11-20 - 0.600.0-dev.0 — 2025-10-07 - 0.500.2 — 2025-06-30 - 0.500.1 — 2025-05-26 - 0.500.0 — 2025-04-25 - 0.500.0-rc.3 — 2025-04-18 - 0.500.0-rc.2 — 2025-04-10 - 0.500.0-rc.1 — 2025-04-09 - … 107 more at https://npm.io/package/@holochain-open-dev/utils/versions ## README # @holochain-open-dev/utils Utilities to build Holochain web applications. ## HoloHashMap Map of `HoloHash` to any JS object. We can't really use well normal JS objects to index by holo hashes because we lose the ability to compare hashes together. Namely, in JS `console.log(new Uint8Array([1]) == new Uint8Array([1]))` prints `false`. ```ts import { AgentPubKey } from "@holochain/client"; import { HoloHashMap } from "@holochain-open-dev/utils"; // Imagine we have out public key const myAgentPubKey = appInfo.cell_info[0].cell_id[1]; const map = new HoloHashMap(); // We can add entries to the dictionary map.set(myAgentPubKey, 1); // Get the value for an entry console.log(map.get(myAgentPubKey)); // Will print `1` // Check if the key exists console.log(map.has(myAgentPubKey)); // Will print `true` // Get iterators for the entries console.log(Array.from(map.keys())); // Will print an array with MYAGENTPUBKEY as the only member console.log(Array.from(map.values())); // Will print `[1]` console.log(Array.from(map.entries())); // Will print an array with `[MYAGENTPUBKEY, 1]` as the only member map.delete(myAgentPubKey); // Will delete this member ``` Some variants exist for this type: - `EntryHashMap` - `ActionHashMap` - `AgentPubKeyMap` - `DnaHashMap` ### LazyHoloHashMap This is an special kind of map, where there is no `set` function, only `get`. Instead, a callback function is passed as the constructor. Then, whenever `get` is called, if it's the first time that the given hash is requested, it will call the callback and initialize the value of the hash with its result. If that hash was already initialized, it will just return that value. ```ts import { AgentPubKey, fakeAgentPubKey } from "@holochain/client"; import { LazyHoloHashMap } from "@holochain-open-dev/utils"; const pubKey = fakeAgentPubKey(); // Imagine we want to fetch the profile of the agent whenever an agent public key is requested const lazyMap = new LazyHoloHashMap((agent: AgentPubKey) => callZome("get_profile", agent) ); console.log(lazyMap.get(pubKey)); // Will print a pending promise // After the request has finished... await lazyMap.get(pubKey); console.log(lazyMap.get(pubKey)); // Will print a completed promise with the value ``` ## EntryRecord Utility to type a single `Record` and extract useful information from them. ```ts import { Record } from '@holochain/client'; import { EntryRecord } from '@holochain-open-dev/utils'; // Imagine a zome function that returns a record, // but we know its entry type const record: Record = await callZome(...); // Then we can type it const profileRecord = new EntryRecord(record); // Access its entry easily const profile: Profile = profileRecord.entry; // Access its action easily, timestamp will be in milliseconds const action: Action = profileRecord.action; // Access its entry hash easily const entryHash: EntryHash = profileRecord.entryHash; // Access its action hash easily const actionHash: ActionHash = profileRecord.actionHash; ``` ## RecordBag Utility to type a list of `Records` and extract useful information from them. ```ts import { Record } from '@holochain/client'; import { RecordBag } from '@holochain-open-dev/utils'; // Imagine a zome function that returns a list of records, // but we know their entry type const records: Record[] = await callZome(...); // Then we can type it const profiles = new RecordBag(records); // Map of entry hash -> entry const profileEntries: EntryHashMap = profiles.entryMap; // Map of action hash -> action // Timestamps are in milliseconds const profileActions: ActionHashMap = profiles.actionMap; // Map of entry hash -> all the actions that have created or updated to that entry const entryActions: EntryHashMap = profiles.entryActions; // For each agent, contains all the actions it has authored const authorMap: AgentPubKeyMap = profiles.authorMap; // Get the array of all records const profileEntries: Array> = profiles.entryRecords; ``` --- _Source: https://npm.io/package/@holochain-open-dev/utils · Machine-readable twin of the npm.io package page. 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