Comparing with context

Read a diff from removed to added, keep unchanged lines around each change, and say what you expected.

A diff is a list of what changed between two versions. The lines without a mark are context — they tell you where you are.

A small diff

  function twoSum(nums, target) {
−   return -1;
+   return [];
  }

Read removed lines first

Look at what was taken away before what was added. Most surprises come from something that quietly disappeared.

Tip: In Shareroom’s Text diff, every changed line carries a + or − marker as well as a colour, so you never compare by eye.