Managing Dependencies with Import Maps

In the previous examples, we used direct URL imports like jsr:@denops/std@^8.0.0. While this works, the recommended approach for Denops plugins (v8.0.0+) is to use import maps with deno.jsonc for cleaner and more maintainable dependency management.

Why Use Import Maps?

The main reason to use import maps is to avoid conflicts between multiple Denops plugins. Each Denops plugin must have a unique directory name under denops/, but root-level configuration files could potentially conflict:

# Multiple plugins installed:
~/.vim/pack/plugins/start/plugin-a/
├── deno.jsonc              # Could conflict
└── denops/plugin-a/        # Always unique

~/.vim/pack/plugins/start/plugin-b/
├── deno.jsonc              # Could conflict  
└── denops/plugin-b/        # Always unique

Some plugin managers have a "merge" feature that combines plugin directories, but even without merging, placing configuration files in plugin-specific directories (denops/plugin-name/) ensures no conflicts can occur regardless of how plugins are installed or managed.

Setting Up Your Plugin Structure

Update your denops-helloworld structure to include configuration files:

denops-helloworld/
├── deno.jsonc                    # Development configuration
├── denops/
│   └── denops-helloworld/
│       ├── deno.jsonc           # Runtime dependencies
│       └── main.ts
└── plugin/
    └── denops-helloworld.vim

Root deno.jsonc (Development)

Create a deno.jsonc in your repository root for workspace configuration:

{
  "workspace": [
    "./denops/denops-helloworld"
  ]
}

This enables Deno commands like deno fmt, deno lint, and deno test to work from your project root and discover your plugin's configuration.

Plugin deno.jsonc (Runtime)

Create denops/denops-helloworld/deno.jsonc for runtime dependencies:

{
  "imports": {
    "@denops/std": "jsr:@denops/std@^8.0.0",
    "@core/unknownutil": "jsr:@core/unknownutil@^4.3.0"
  }
}

Updating Your Code

With import maps configured, update your imports from:

import type { Entrypoint } from "jsr:@denops/std@^8.0.0";
import { assert, is } from "jsr:@core/unknownutil@^4.3.0";

To cleaner versions:

import type { Entrypoint } from "@denops/std";
import { assert, is } from "@core/unknownutil";

Alternative: import_map.json

Denops also supports import_map.json(c) files, but they require more verbose configuration due to the Import Maps Standard:

// denops/denops-helloworld/import_map.json
{
  "imports": {
    "@denops/std": "jsr:@denops/std@^8.0.0",
    "@denops/std/": "jsr:/@denops/std@^8.0.0/" // Required for submodules
  }
}

We recommend using deno.jsonc as it's less verbose and integrates better with Deno tooling. For more details about the differences, see the Deno documentation.

Benefits

1. Cleaner imports: No more long URLs in your code
2. Version management: Update dependencies in one place
3. Better IDE support: Auto-completion and type checking work seamlessly
4. No conflicts: Each plugin manages its own dependencies
5. Development tools: Format and lint your code from the project root