optional-require

What is optional-require?

The 'optional-require' npm package allows you to require modules that may or may not exist without throwing an error. This is useful for optional dependencies or plugins that are not always needed.

What are optional-require's main functionalities?

Basic Optional Require

This feature allows you to require a module that may not be installed. If the module is not available, it returns null instead of throwing an error.

const optionalRequire = require('optional-require')(require);
const myModule = optionalRequire('my-module');
if (myModule) {
  console.log('my-module is available');
} else {
  console.log('my-module is not available');
}

Optional Require with Default Value

This feature allows you to provide a default value if the module is not available. This can be useful to ensure your code continues to work even if the optional module is missing.

const optionalRequire = require('optional-require')(require);
const myModule = optionalRequire('my-module', { default: {} });
console.log(myModule);

Optional Require with Logging

This feature allows you to log a custom message if the module is not available. This can be useful for debugging or informing the user about missing optional dependencies.

const optionalRequire = require('optional-require')(require);
const myModule = optionalRequire('my-module', { message: 'my-module is not installed' });
if (!myModule) {
  console.log('my-module is not installed');
}

Other packages similar to optional-require

require-optional

The 'require-optional' package provides similar functionality by allowing you to require modules that may not be installed. It also returns null if the module is not available, but it does not provide options for default values or custom logging messages.

try-require

The 'try-require' package attempts to require a module and returns undefined if the module is not found. It is similar to 'optional-require' but does not offer as many customization options such as default values or custom messages.

README

Optional Require

node.js require that let you handle module not found error without try/catch. Allows you to gracefully require a module only if it exists and contains no error.

Why not try/catch?

So why not just do:

let some;
try {
  some = require("some-optional-module");
} catch {
  // do nothing
}

1. You need to keep the variable outside: let some before try/catch
2. If "some-optional-module" contains error itself, above code will silently ignore it, leaving you, and more importantly, your users, puzzling on why it's not working.

Usage

TypeScript:

import { optionalRequire } from "optional-require";

const some = optionalRequire("some-optional-module");

JavaScript:

const { optionalRequire } = require("optional-require");

const foo = optionalRequire("foo") || {};
const bar = optionalRequire("bar", true); // true enables console.log a message when not found
const xyz = optionalRequire("xyz", "test"); // "test" enables console.log a message with "test" added.
const fbPath = optionalRequire.resolve("foo", "foo doesn't exist");
// relative module path works - *but* you need to pass in `require` from your file
const rel = optionalRequire("../foo/bar", { require });

Binding require

The default optionalRequire uses require from the context of this module. While you can pass in your require in options, if you want to create your own function that's bound to your require, you can do it with makeOptionalRequire:

import { makeOptionalRequire } from "optional-require";

const optionalRequire = makeOptionalRequire(require);

// now you can optional require files in same dir as your file
const myModule = optionalRequire("./my-module");

Legacy Usage

In older versions, this module exports makeOptionalRequire directly and this is the legacy usage in JavaScript, which is still supported:

const optionalRequire = require("optional-require")(require);

const foo = optionalRequire("foo") || {};
const bar = optionalRequire("bar", true); // true enables console.log a message when not found
const xyz = optionalRequire("xyz", "test"); // "test" enables console.log a message with "test" added.
const fbPath = optionalRequire.resolve("foo", "foo doesn't exist");
const rel = optionalRequire("../foo/bar"); // relative module path works

API

https://jchip.github.io/optional-require/modules.html#optionalrequire

LICENSE

Apache-2.0 © Joel Chen