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Validate the JavaScript code of your Markdown files.

Codeship Status for Huemul/chimi

Table of contents

  1. The problem
  2. This solution
  3. Installation
  4. Usage
  5. Configuration
  6. Inspiration
  7. Similar and complementary tools

The problem

A great OpenSource project is only as great as its documentation.

Probably me.

We ideally test our code and care about its quality, but not so much about documentation. Snippets of code in the docs sometimes have typos or even are out of sync with the library version.

This solution

chimi aims to bring the same principles we use for automating tests of our code to test the documentation. It parses Markdown files and runs the JavaScript snippets to check if everything is alright.


$ yarn add chimi --dev
$ npm i chimi --save-dev

Global works too:

$ yarn global add chimi
$ npm i -g chimi


  Validate the JavaScript code of your Markdown files

  $ chimi -f <file>

    --file,    -f      File or glob matching multiple files (default: "")
    --help,    -h      Show help
    --silent           Prevent snippets from printing messages through the console
    --version, -v, -V  Show version

    $ chimi -f

    $ chimi -f 'doc/*.md'


To let chimi find the snippets you have to indicate the snippet language using either js or javascript like so:


You can configure chimi using a configuration file, it might be a JSON or JavaScript file (chimi.config.js, .chimirc) or the chimi property in the package.json:

  "dependencies": [
    { "module": "lodash", "name": "_" },
    { "module": "./config", "name": "config" },
    { "module": "es6-promise" }
  "globals": {
    "answer": 42,
    "add": "(a, b) => a + b",
    "message": "'hello world'",
    "fruits": "['orange', 'apple']",
    "config": "{ port: 8080 }"
  "aliases": {
    "my-lib": "./dist/my-lib"
  "file": "",
  "timeout": 5000

NOTE: the .chimirc file has to be a valid JSON. If it is a JavaScript file, an object has to be exported.

dependencies: Array<string|object>

A list of dependencies to be required on each snippet.

Pass a string when the variable name and the module to be required are equal. To cover other cases you can pass an object with variable name as the name property, the module as the module property, if the name is missing the require will not have an assignment.

The dependencies in the example will generate these requires:

const trae   = require('trae')
const _      = require('lodash')
const config = require('./config')


These dependencies will be added to your snippet before running it so you don't have to do it on every snippet. You can use it to implicitly refer to your project or to do some setup for the snippets (i.e. mock an http request).

globals: object

A list of variable declarations to add on each snippet. Each key represents the variable name and the value is, well, the value.

The globals in the example will generate these declarations:

let answer  = 42
let add     = (a, b) => a + b
let message = 'hello world'
let fruits  = ['orange', 'apple']
let port    = { port: 8080 }

NOTE: strings must be quoted. E.g. consider the following example.

  "globals": {
    "wrong": "hello world"
    "right": "'hello world'"
let wrong = hello world
let right = 'hello world'

aliases: object

An object containing aliases for imports and requires, with the format { [path/module to replace]: alias }.

The alias in the example will transform following snippet:

import myLib from 'my-lib'

const lib = require('my-lib')

to this before running it.

import myLib from './dist/my-lib'

const lib = require('./dist/my-lib')

file: string


The path to the file/s you want to parse. It can also be a glob. Be sure to specify only .md files.

timeout: number

Default: 5000.

The time, in miliseconds, to wait for the snippet execution before considering it a failure.

Snippet annotations

Markdown snippets can be annotated by adding extra stuff on the same line as the language. Don't worry this annotations do not show on the web.

Chimi supports the following annotations:


To skip a snippet from running:

```js (skip)

This is useful when the snippet has purposely incompleted or broken code.


chimi was inspired on budziq's rust-skeptic, a similar tool for Rust, by franleplant suggestion:

would be cool to have it [rust-skeptic] for JS.

Similar and complementary tools

There are other tools that will help you improve your JS in Markdown.

  • prettier: Formats JavaScript and other languages. Since v1.8 it supports formatting JS snippets inside Markdown files.

  • eslint-plugin-markdown: Lints JavaScript code blocks in Markdown documents. Since chimi runs the code, there are things eslint could miss, e.g. you added a breaking change to the library but forgot to update your docs. But if you only want to lint your code, then eslint-plugin-markdown is all you need.