Monorepo-lens

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Flexible tool to analyze and visualize dependencies in your monorepo

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Who is it for?

• You have packages stored in monorepo
• Some packages depends on other ones
• You want to develop, build and test packages faster
• You want to analyze dependencies automatically

How it works

• Collectors - packages, that can collect information about dependencies between packages in monorepo. Monorepo-lens starts from collectors to get infromation about packages and dependencies
• Lenses - packages for calculation metrics dependant on packages tree. Monorepo-lens uses it to calculate metrics for each package
• Reporters - packages for representing lenses results with different formats. Monorepo-lens runs reporters at the end and pass data from collector and lenses to they

Each of these steps can include multiple packages. For example: 1 collector for lerna, 2 lenses for regression testing cost and library removing progress and 2 reporters for HTML and JSON view.

How to start

• install monorepo-lens globally npm i -g monorepo-lens or to the workspace root
• install necessary collector, lenses and reporters to workspace. We suggest to start with @monorepo-lens/regress-cost-lens and @monorepo-lens/interactive-reporter
• configure cli using monorepo-lens configure from monorepo root
• run it with npx monorepo-lens run

Why not "tool X"

• We tried to use nx and lerna@5 with nx visualization. It is not adapted for automatic analyzing and reviewing large monorepos. This is a screenshot of our monorepo visualized with nx. It freezed for a minute and produced a hard-to-read graph

Configuration

Configuration provided by cosmiconfig and can be stored in different formats. monorepo-lens configure produces .repolensrc file.

Configuration contains 3 sections: collectors, lenses and reporters. Each of this section is object where key is name of package and value is object for this package.

Config for monorepo-lens monorepo you can find here

How to develop

Each part of monorepo-lens (collector, lense, reporter) is a simple async function. It takes result of previous part and configuration in arguments and produces result for the next part.

• Create a package with clear name. We suggest to start name with monorepo-lens prefix and end with part you want to develop (collector, lense, reporter). For example: monorepo-lens-god-module-lense
• Install @monorepo-lens/schemas to devDependencies. It will helps with interfaces for your package
• Export default function from main file of this package with right interface:
  • for collector: import { Collector } from '@monorepo-lens/schemas';
  • for lense: import { Lense } from '@monorepo-lens/schemas';
  • for reporter: import { Reporter } from '@monorepo-lens/schemas';
• Implement this interface

How to develop in this monorepo

• install latest version of pnpm: npm i -g pnpm
• install dependencies: pnpm i
• start watching for changes in packages: pnpm -r --parallel --stream watch