mathjs/examples/node_modules/rechoir/lib/extension.js

Math.js is an extensive math library for JavaScript and Node.js. It features a flexible expression parser with support for symbolic computation, comes with a large set of built-in functions and constants, and offers an integrated solution to work with dif

var path = require('path');

var EXTRE = /\.[^.]*/g;
var LONGEXTRE = /^[.]?[^.]+([.].+[^.])$/;

module.exports = function(input) {
  var basename = path.basename(input);
  var longExtension = LONGEXTRE.exec(basename);
  if (!longExtension) {
    return;
  }
  var possibleExtensions = longExtension[1].match(EXTRE);
  if (!possibleExtensions) {
    return;
  }
  return possibleExtensions.map(function(_, idx, exts) {
    return exts.slice(idx).join('');
  });
};