sort an array by specified key values matching a given array of values. (used for metalsmith-collections, and metalsmith-collections-tree)

readme.md

Sort an array by specified key values matching a given array of values. (used for metalsmith-collections, and metalsmith-collections-tree)

metalsmith-collections

metalsmith-collections-tree

metalsmith example:

const sortByArray = require('./sortByArray.js');

... 
          use(collections({
            'cool-products': {
              pattern: ['products/cool-products/*'],
              sortBy: sortByArray('name', [
                'c-page-name',
                'a-page-name',
                'b-page-name'
              ])
            }
          })
...

sortByArray.js

'use strict';

/**
 * Generate a custom sort method for given starting `order`. After the given
 * order, it will ignore casing and put periods last.
 *
 * sort descending by key with array items first.
 *   sortByArray('title', ['Home']);
 *
 * That is passed:
 *
 *   - Home
 *   - About
 *   - JavaScript
 *   - HTML
 *   - CSS
 *   - .NET
 *
 * Would guarantee that 'Home' ends up first, with the casing in 'iOS'
 * ignored so that it falls in the normal alphabetical order, and puts '.NET'
 * last since it starts with a period.
 *
 * alternatively you may ommit the sort array.
 * sort descending by key if no array is passed.
 *   sorter('title'); 
 *
 * @param {string} keyName
 * @param {Array} order
 * @return {Function}
 */
module.exports = (k = 'name', s = []) => (a, b) => {
  let k1 = a[k], k2 = b[k];
  if (!k1 && !k2) return 0;
  if (!k1) return 1;
  if (!k2) return -1;
  let is1 = s.indexOf(k1), is2 = s.indexOf(k2);
  if (~is1 && ~is2) return is1 < is2 ? -1 : is2 < is1 ? 1 : 0;
  if (~is1) return -1;
  if (~is2) return 1;
  k1 = k1.toLowerCase();
  k2 = k2.toLowerCase();
  // move matches with . to the end
  return '.' === k1[0] ? 1 : '.' === k2[0] || k1 < k2 ? -1 : k2 < k1 ? 1 : 0;
};