@zaeny/literate

var {extractCode}  = require('@zaeny/literate');
var testMdFile = fs.readFileSync('./test.md', 'utf8');

extractCode(testMdFile);

/*
  [
  { path: 'index.js', lang: 'js', code: "console.log('welcome');" },
  { path: 'index.js', lang: 'js', code: "console.log('hai');" }
]
*/

var {eval} = require('@zaeny/literate/eval');
eval(testMdFile);
/*
  welcome
  hai
*/

var {tangle} = require('@zaeny/literate/tangle');
tangle(testMdFile);
/*
  'tangle files: #1 index.js'
*/

eval(string, validatorFn)
eval(testMdFile, (file) => (file.code && file.lang === "js" && file.eval===1));
// welcome
// hai

tangle(testMdFile, (file) => (file.path && file.lang === "js"));
//  'tangle files: #1 index.js'