New flow.until_flows api (#17)

Co-authored-by: Mikhail Gudkov <[email protected]>

ludobits/m/flow.lua

@@ -490,6 +490,27 @@ function M.play_animation(sprite_url, id)
 	end)
 end
 
+--- Wair until other flow coroutines were finished
+-- @param flows one coroutine or array of coroutines
+function M.until_flows(flows)
+	assert(flows)
+
+	-- single coroutine
+	if flows.co then
+		M.until_true(function()
+			return coroutine.status(flows.co) == "dead"
+		end)
+		return
+	end
+
+	-- several coroutines
+	for k, v in pairs(flows) do
+		M.until_true(function()
+			return coroutine.status(v.co) == "dead"
+		end)
+	end
+end
+
 function M.ray_cast()
 	print("flow.ray_cast() is deprecated. Use synchronous ray casts released in Defold 1.2.150 instead!")
 end

test/test_flow.lua

@@ -175,5 +175,28 @@ return function()
 			wait_seconds(0.25)
 			assert(flow_finished)
 		end)
+
+		it("should be possible to pause until flows complete", function()
+			local flow_finished = false
+			local instance = flow.start(function()
+				local f1 = flow.parallel(function()
+					flow.delay(0.3)
+				end)
+
+				local f2 = flow.parallel(function()
+					flow.delay(0.3)
+				end)
+
+				flow.until_flows(f1)
+				flow.until_flows({ f1, f2 })
+				flow_finished = true
+			end)
+
+			wait_seconds(0.2)
+			assert(not flow_finished)
+
+			wait_seconds(0.2)
+			assert(flow_finished)
+		end)
 	end)
 end