Runtime: Add table extensions for key and value retrieval

Trivial stuff, but no point in recreating them again and again.

Runtime/Extensions/tablex.lua

@@ -4,6 +4,8 @@ local ipairs = ipairs
 local pairs = pairs
 local type = type
 
+local table_insert = table.insert
+
 function table.contains(table, value)
 	validation.validateTable(table, "table")
 
@@ -77,5 +79,27 @@ function table.invert(tableToInvert)
 	return invertedTable
 end
 
+function table.keys(table)
+	validation.validateTable(table, "table")
+
+	local keys = {}
+	for key, value in pairs(table) do
+		table_insert(keys, key)
+	end
+
+	return keys
+end
+
+function table.values(table)
+	validation.validateTable(table, "table")
+
+	local values = {}
+	for key, value in pairs(table) do
+		table_insert(values, value)
+	end
+
+	return values
+end
+
 table.clear = require("table.clear")
 table.new = require("table.new")

Tests/BDD/table-library.spec.lua

@@ -153,4 +153,48 @@ describe("table", function()
 			assertEquals(table.invert(input), expectedOutput)
 		end)
 	end)
+
+	describe("keys", function()
+		it("should throw if a non-table value was passed as the first parameter", function()
+			assertThrows(function()
+				table.keys(nil)
+			end, "Expected argument table to be a table value, but received a nil value instead")
+		end)
+
+		it("should return a list of keys for both the array and the dictionary part of the given table", function()
+			local someTable = {
+				A = 42,
+				B = 123,
+				"Hello",
+				"world",
+			}
+			local keys = table.keys(someTable)
+			assertTrue(table.contains(keys, 1))
+			assertTrue(table.contains(keys, 2))
+			assertTrue(table.contains(keys, "A"))
+			assertTrue(table.contains(keys, "B"))
+		end)
+	end)
+
+	describe("values", function()
+		it("should throw if a non-table value was passed as the first parameter", function()
+			assertThrows(function()
+				table.values(nil)
+			end, "Expected argument table to be a table value, but received a nil value instead")
+		end)
+
+		it("should return a list of values for both the array and the dictionary part of the given table", function()
+			local someTable = {
+				A = 42,
+				B = 123,
+				"Hello",
+				"world",
+			}
+			local values = table.values(someTable)
+			assertTrue(table.contains(values, 42))
+			assertTrue(table.contains(values, 123))
+			assertTrue(table.contains(values, "Hello"))
+			assertTrue(table.contains(values, "world"))
+		end)
+	end)
 end)