Runnable README files
npm install runmdRun code blocks in your markdown and annotate them with the output.
Creating README files is a pain, especially when it comes to writing code
samples. Code gets out of date, authors get sloppy, details get omitted, etc.
RunMD takes the pain out of this process.
With RunMD, your readers can trust your code blocks are runnable and that code
output will be as-claimed.
``shell`
npm install runmd
runmd [options] input_file
Where options may be zero or more of:
- --output=output_file file to write specify an output file--watch
- Watch input_file for changes and rerender--lame
- Suppress attribution footer
For example, to port an existing README.md file:
cp README.md README_js.md
Edit README_js.md to add Markdown Options (below) to your ``javascript
blocks, then ...
runmd README_js.md --output README.md
RunMD scripts are run using Node.js' vm module.
This environment is limited in "interesting" ways, and RunMD runs fast and loose with some APIs. Specifically:
- console.log() works, but no other console methods are supported at this
time
- setTimeout() works, but all timers fire immediately at the end of script
execution. clearTimeout, setInterval, and clearInterval are not
supported
[Note: PRs fleshing out these and other missing APIs would be "well received"]
Some ES6 import incantations will work, however this feature should be
considered very experimental at this point. Read the source for
details.
To avoid publishing when compilation of your README file fails:
"scripts": {
"prepare": "runmd README_js.md --output README.md"
}
Runs the script, appending any console.log output. E.g.:
``javascript --run`
console.log('Hello, World!');
... becomes:
`javascript
console.log('Hello, World!');
⇒ Hello, World!
``
--run may be omitted if other options are present.
If a context_name is provided, all blocks with that name will share the same
runtime context. E.g.
`javascript --run sample`
let text = 'World';
Continuing on ...
`javascript --run sample`
console.log(text);
... becomes:
`javascript`
let text = 'Hello';
Continuing on ...
`javascript
console.log(text);
⇒ Hello
`
... but trying to reference text in a new context or other named context will
fail:
`javascript --run`
console.log(text);
(Results in ReferenceError: text is not defined.)
Run the script, but do not render the script source or output. This is useful
for setting up context that's necessary for code, but not germane to
documentation.
Welcome!
`javascript --run foo --hide`
// Setup/utility code or whatever ...
function hello() {
console.log('Hello, World!');
}
Here is a code snippet:
`javascript --run foo`
hello();
... becomes:
Welcome!
Here's a code snippet:
`javascript
hello();
⇒ Hello, World!
`
Inline values _for single line expressions_ may be displayed by appending
"// RESULT" to the end of a line. Note: RunMD will error if the line is not a
self-contained, evaluate-able, expression.
`javascript --run`
['Hello', ' World!'].join(','); // RESULT
... becomes:
`javascript`
['Hello', ' World!'].join(','); // ⇨ 'Hello, World!'
A global runmd object is provided all contexts, and supports the following:
The onRequire event gives pages the opportunity to transform module require
paths. This is useful if the module context in which you render markdown is
different from what your readers will typically encounter. (Often the case with
npm-published modules).
`javascript --hiderequire('uuid/') to
// Remap require('./')
runmd.onRequire = function(path) {
return path.replace(/^uuid\//, './');
}
`
The onOutputLine event gives pages the opportunity to transform markdown output.
`javascript --hide`
runmd.onOutputLine = function(line, isRunning) {
return !isRunning ? line.toUpperCase() : line);
}
The isRunning argument will be true for any lines that are interpreted as
code by this module. Transformations do not affect interpreted source, only how
source is rendered.
Return null to omit the line from the rendered output.
There's more than one way to visualize changes to Markdown files as you edit
them, but the following works pretty well for me:
- Install the Markdown Preview Plus Chrome
- ... Allow it to access file URLs" (in chrome://extensions tab)
- ... Set Reload Frequency to "1 second" (in the extension options)
- Launch runmd with the --watch` option to have it continuously re-render your output file as you make changes
- Open the output file in Chrome, and it will update in realtime as you make changes to your runmd input file(s)
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Markdown generated from src/README_js.md by