Introduction to Effect Platform

@effect/platform is a library for building platform-independent abstractions in environments such as Node.js, Deno, Bun, and browsers.

With @effect/platform, you can integrate abstract services like FileSystem or Terminal into your program. When assembling your final application, you can provide specific layers for the target platform using the corresponding packages:

• @effect/platform-node for Node.js or Deno
• @effect/platform-bun for Bun
• @effect/platform-browser for browsers

Stable Modules

The following modules are stable and their documentation is available on this website:

Installation

To install the beta version:

npm install @effect/platform@rc

pnpm add @effect/platform@rc

yarn add @effect/platform@rc

bun add @effect/platform@rc

deno add npm:@effect/platform@rc

Getting Started with Cross-Platform Programming

Here’s a basic example using the Path module to create a file path, which can run across different environments:

Example (Cross-Platform Path Handling)

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import { Effect, Path } from "effect"
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const program = Effect.gen(function* () {
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  // Access the Path service
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  const path = yield* Path.Path
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  // Join parts of a path to create a complete file path
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  const mypath = path.join("tmp", "file.txt")
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  console.log(mypath)
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  return mypath
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})
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Effect.runSync(program.pipe(Effect.provide(Path.layer))) // => "tmp/file.txt"

Running the Program in Node.js or Deno

First, install the Node.js-specific package:

npm install @effect/platform-node@rc

pnpm add @effect/platform-node@rc

yarn add @effect/platform-node@rc

deno add npm:@effect/platform-node@rc

Update the program to load the Node.js-specific context:

Example (Providing Node.js Context)

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import { Effect, Path } from "effect"
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import { NodeServices, NodeRuntime } from "@effect/platform-node"
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const program = Effect.gen(function* () {
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  // Access the Path service
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  const path = yield* Path.Path
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  // Join parts of a path to create a complete file path
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  const mypath = path.join("tmp", "file.txt")
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  console.log(mypath)
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})
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NodeRuntime.runMain(program.pipe(Effect.provide(NodeServices.layer)))

Finally, run the program in Node.js using tsx, or directly in Deno:

npx tsx index.ts

pnpm dlx tsx index.ts

yarn dlx tsx index.ts

deno run index.ts
# or

deno run -RE index.ts
# Output: tmp/file.txt
# (granting required Read and Environment permissions without being prompted)

Running the Program in Bun

To run the same program in Bun, first install the Bun-specific package:

bun add @effect/platform-bun@rc

Update the program to use the Bun-specific context:

Example (Providing Bun Context)

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import { Effect, Path } from "effect"
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import { BunServices, BunRuntime } from "@effect/platform-bun"
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const program = Effect.gen(function* () {
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  // Access the Path service
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  const path = yield* Path.Path
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  // Join parts of a path to create a complete file path
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  const mypath = path.join("tmp", "file.txt")
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  console.log(mypath)
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})
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BunRuntime.runMain(program.pipe(Effect.provide(BunServices.layer)))

Run the program in Bun:

bun index.ts
tmp/file.txt