All files / lib/internal linkedlist.js

100% Statements 54/54
100% Branches 13/13
100% Functions 5/5
100% Lines 54/54

Press n or j to go to the next uncovered block, b, p or k for the previous block.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 5517x 17x 13x 13x 13x 13x 17x 17x 15915x 15915x 15067x 15915x 17x 17x 27712x 27712x 26961x 26961x 27712x 27712x 26961x 26961x 27712x 27712x 27712x 27712x 17x 17x 16175x 16175x 14040x 14040x 16175x 16175x 16175x 16175x 16175x 16175x 16175x 16175x 16175x 16175x 17x 1215x 1215x 1215x 17x 17x 17x 17x 17x 17x 17x 17x  
'use strict';
 
function init(list) {
  list._idleNext = list;
  list._idlePrev = list;
}
 
// Show the most idle item.
function peek(list) {
  if (list._idlePrev === list) return null;
  return list._idlePrev;
}
 
// Remove an item from its list.
function remove(item) {
  if (item._idleNext) {
    item._idleNext._idlePrev = item._idlePrev;
  }
 
  if (item._idlePrev) {
    item._idlePrev._idleNext = item._idleNext;
  }
 
  item._idleNext = null;
  item._idlePrev = null;
}
 
// Remove an item from its list and place at the end.
function append(list, item) {
  if (item._idleNext || item._idlePrev) {
    remove(item);
  }
 
  // Items are linked  with _idleNext -> (older) and _idlePrev -> (newer).
  // Note: This linkage (next being older) may seem counter-intuitive at first.
  item._idleNext = list._idleNext;
  item._idlePrev = list;
 
  // The list _idleNext points to tail (newest) and _idlePrev to head (oldest).
  list._idleNext._idlePrev = item;
  list._idleNext = item;
}
 
function isEmpty(list) {
  return list._idleNext === list;
}
 
module.exports = {
  init,
  peek,
  remove,
  append,
  isEmpty
};