@fluidframework/map

Using Fluid Framework libraries

When taking a dependency on a Fluid Framework library's public APIs, we recommend using a ^ (caret) version range, such as ^1.3.4. While Fluid Framework libraries may use different ranges with interdependencies between other Fluid Framework libraries, library consumers should always prefer ^.

If using any of Fluid Framework's unstable APIs (for example, its beta APIs), we recommend using a more constrained version range, such as ~.

Installation

To get started, install the package by running the following command:

npm i @fluidframework/map

Importing from this package

This package leverages package.json exports to separate its APIs by support level. For more information on the related support guarantees, see API Support Levels.

To access the public (SemVer) APIs, import via @fluidframework/map like normal.

To access the legacy APIs, import via @fluidframework/map/legacy.

API Documentation

API documentation for @fluidframework/map is available at https://fluidframework.com/docs/apis/map.

SharedMap

The SharedMap distributed data structure can be used to store key-value pairs. It provides the same API for setting and retrieving values that JavaScript developers are accustomed to with the Map built-in object.

Creation

To create a SharedMap, call the static create method:

const myMap = SharedMap.create(this.runtime, id);

Usage

Unlike the JavaScript Map, a SharedMap's keys must be strings. The value must only be plain JS objects or handles (e.g. to another DDS or Fluid objects).

In collaborative scenarios, the value is settled with a policy of last write wins.

Eventing

SharedMap is an EventEmitter, and will emit events when other clients make modifications. You should register for these events and respond appropriately as the data is modified. valueChanged will be emitted in response to a set or delete, and provide the key and previous value that was stored at that key. clear will be emitted in response to a clear.

SharedDirectory and IDirectory

A SharedDirectory is a map-like DDS that additionally supports storing key/value pairs within a tree of subdirectories. This subdirectory tree can be used to give hierarchical structure to stored key/value pairs rather than storing them on a flat map. Both the SharedDirectory and any subdirectories are IDirectories.

Creation

To create a SharedDirectory, call the static create method:

const myDirectory = SharedDirectory.create(this.runtime, id);

Usage

The map operations on an IDirectory refer to the key/value pairs stored in that IDirectory, and function just like SharedMap including the same extra functionality and restrictions on keys and values. To operate on the subdirectory structure, use the corresponding subdirectory methods.

getWorkingDirectory()

To "navigate" the subdirectory structure, IDirectory provides a getWorkingDirectory method which takes a relative path and returns the IDirectory located at that path if it exists.

Eventing

valueChanged events additionally provide the absolute path to the subdirectory storing the value that changed.

dispose events are fired on sub directory which is deleted. Any access to this sub directory will throw an error once it is disposed.

Minimum Client Requirements

These are the platform requirements for the current version of Fluid Framework Client Packages. These requirements err on the side of being too strict since within a major version they can be relaxed over time, but not made stricter. For Long Term Support (LTS) versions this can require supporting these platforms for several years.

It is likely that other configurations will work, but they are not supported: if they stop working, we do not consider that a bug. If you would benefit from support for something not listed here, file an issue and the product team will evaluate your request. When making such a request please include if the configuration already works (and thus the request is just that it becomes officially supported), or if changes are required to get it working.

Supported Runtimes

• NodeJs ^20.10.0 except that we will drop support for it when NodeJs 20 loses its upstream support on 2026-04-30, and will support a newer LTS version of NodeJS (22) at least 1 year before 20 is end-of-life. This same policy applies to NodeJS 22 when it is end of life (2027-04-30).
• Modern browsers supporting the es2022 standard library: in response to asks we can add explicit support for using babel to polyfill to target specific standards or runtimes (meaning we can avoid/remove use of things that don't polyfill robustly, but otherwise target modern standards).

Supported Tools

• TypeScript 5.4:
  • All strict options are supported.
  • strictNullChecks is required.
  • Configuration options deprecated in 5.0 are not supported.
  • exactOptionalPropertyTypes is currently not fully supported. If used, narrowing members of Fluid Framework types types using in, Reflect.has, Object.hasOwn or Object.prototype.hasOwnProperty should be avoided as they may incorrectly exclude undefined from the possible values in some cases.
• webpack 5
  • We are not intending to be prescriptive about what bundler to use. Other bundlers which can handle ES Modules should work, but webpack is the only one we actively test.

Module Resolution

Node16, NodeNext, or Bundler resolution should be used with TypeScript compilerOptions to follow the Node.js v12+ ESM Resolution and Loading algorithm. Node10 resolution is not supported as it does not support Fluid Framework's API structuring pattern that is used to distinguish stable APIs from those that are in development.

Module Formats

• ES Modules: ES Modules are the preferred way to consume our client packages (including in NodeJs) and consuming our client packages from ES Modules is fully supported.

• CommonJs: Consuming our client packages as CommonJs is supported only in NodeJS and only for the cases listed below. This is done to accommodate some workflows without good ES Module support. If you have a workflow you would like included in this list, file an issue. Once this list of workflows motivating CommonJS support is empty, we may drop support for CommonJS one year after notice of the change is posted here.

  • Testing with Jest (which lacks stable ESM support due to unstable APIs in NodeJs)

Contribution Guidelines

There are many ways to contribute to Fluid.

• Participate in Q&A in our GitHub Discussions.
• Submit bugs and help us verify fixes as they are checked in.
• Review the source code changes.
• Contribute bug fixes.

Detailed instructions for working in the repo can be found in the Wiki.

This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact [email protected] with any additional questions or comments.

This project may contain Microsoft trademarks or logos for Microsoft projects, products, or services. Use of these trademarks or logos must follow Microsoft’s Trademark & Brand Guidelines. Use of Microsoft trademarks or logos in modified versions of this project must not cause confusion or imply Microsoft sponsorship.

Help

Not finding what you're looking for in this README? Check out fluidframework.com.

Still not finding what you're looking for? Please file an issue.

Thank you!

Trademark

This project may contain Microsoft trademarks or logos for Microsoft projects, products, or services.

Use of these trademarks or logos must follow Microsoft's Trademark & Brand Guidelines.

Use of Microsoft trademarks or logos in modified versions of this project must not cause confusion or imply Microsoft sponsorship.