All files / lib/internal linkedlist.js

31.48% Statements 17/54
100% Branches 1/1
0% Functions 0/5
31.48% Lines 17/54

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 5595x 95x         95x 95x         95x 95x                         95x 95x                             95x       95x 95x 95x 95x 95x 95x 95x 95x  
'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
};