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> When you make a change you test it live in the REPL. This is no different from running a unit test. What?

• yogthos 13y ago
  Let's say I have a function that pulls some data from the database and transforms it in some way. I can run the original function and capture its output. Then I can write an updated function, see what its output is, I can compare them visually to ensure the change I made works as intended. When you don't have a REPL the only way to do this is by writing a test and running it once you've made the change. In fact, you can use the code from the tests you write in the REPL to create a unit test for later. The difference is that the REPL feedback loop is much tighter.