denoland-deno/docs/examples/manage_dependencies.md

# Managing Dependencies

In Deno there is no concept of a package manager as external modules are
imported directly into local modules. This raises the question of how to manage
remote dependencies without a package manager. In big projects with many
dependencies it will become cumbersome and time consuming to update modules if
they are all imported individually into individual modules.

The standard practice for solving this problem in Deno is to create a `deps.ts`
file. All required remote dependencies are referenced in this file and the
required methods and classes are re-exported. The dependent local modules then
reference the `deps.ts` rather than the remote dependencies.

This enables easy updates to modules across a large codebase and solves the
'package manager problem', if it ever existed. Dev dependencies can also be
managed in a separate `dev_deps.ts` file.

**deps.ts example**

```ts
/**
 * deps.ts re-exports the required methods from the remote Ramda module.
 **/
export {
  add,
  multiply,
} from "https://x.nest.land/ramda@0.27.0/source/index.js";
```

In this example the same functionality is created as is the case in the
[local and remote import examples](./import_export.md). But in this case instead
of the Ramda module being referenced directly it is referenced by proxy using a
local `deps.ts` module.

**Command:** `deno run dependencies.ts`

```ts
import {
  add,
  multiply,
} from "./deps.ts";

function totalCost(outbound: number, inbound: number, tax: number): number {
  return multiply(add(outbound, inbound), tax);
}

console.log(totalCost(19, 31, 1.2));
console.log(totalCost(45, 27, 1.15));

/**
 * Output
 *
 * 60
 * 82.8
 */
```