All files / lib/internal linkedlist.js

100% Statements 55/55
100% Branches 13/13
100% Functions 5/5
100% Lines 55/55

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 55 5621x 21x 50x 50x 50x 50x 50x 21x 21x 20060x 20060x 18424x 20060x 21x 21x 30895x 30895x 30464x 30464x 30895x 30895x 30464x 30464x 30895x 30895x 30895x 30895x 21x 21x 18964x 18964x 15193x 15193x 18964x 18964x 18964x 18964x 18964x 18964x 18964x 18964x 18964x 18964x 21x 866x 866x 866x 21x 21x 21x 21x 21x 21x 21x 21x  
'use strict';
 
function init(list) {
  list._idleNext = list;
  list._idlePrev = list;
  return 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
};