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Working with data · 18 / 69

Copies and aliases

YOUR TASK

Make this happen

3 steps

  1. Assigning a table to another variable shares the same table. Create a fresh record when an update must leave the original unchanged.

  2. Read the cases in lesson.test.lua, then choose Check solution to see what needs to change.

  3. Update subject.lua until every test passes. Keep the supplied tests unchanged.

Start with Check solution, then use the failures to guide your edits.

Read the starter and tests

subject.lua

exports.rename = function(item: { name: string }, name: string)
  local copy = item
  copy.name = name
  return copy
end

lesson.test.lua

local t = require("test")
local subject = require("cococo.subject")

t.it("returns new name", function()
  local s = subject.load()
  t.expect(s.rename({ name = "old" }, "new").name):eq("new")
end)

t.it("preserves original", function()
  local s = subject.load()
  local item = { name = "old" }
  s.rename(item, "new")
  t.expect(item.name):eq("old")
end)