convert string to array of ordinary strings and key-named strings

splitByKeys.js

// convert string to array of ordinary strings and key-named strings
function splitByKeys(pattern) {
  let regexp = /(:\w+)/g;
  return pattern
    .split(regexp)
    // remove trailings
    .filter(function(str) { return !!str; })
  ;
}

splitByKeys('/topic/:date/:name'); // ['/topic/', ':date', '/', ':name']
splitByKeys('/topic/:slug/2015/02/12/:name'); // ['/topic/', ':slug', '/2015/02/12/', ':name']