An conceptual javascript utility library for array-like objects requiring a very limited interface:

var ArrayLike = function () {
  this.length = 0;

  /* iteration */
  this.reduce = function (callback[, initialValue]) {};

  /* mutation */
  this.splice = function (start, deleteCount[, item1[, item2[, ...]]]) {};
};

The objectives is to clearly demonstrate the flexibility of Array#reduce, Array#splice and then to a lesser extent... you know... be accurate and robust. That being said, there is a smattering of unit tests to back it up.

• reduce, foldl, inject
• reduceRight, foldr
• map, collect
• forEach, each
• filter, select
• reject
• contains, includes, include
• compact
• some, any
• all, every
• find, detect
• findIndex
• first, head, take
• rest, tail, drop
• groupBy
• countBy
• indexBy
• partition
• flatten
• shuffle
• sample
• reverse
• min, max
• intersection
• union
• unique, uniq
• invoke
• slice

• random
• negate
• identity
• toArray