Functions That Take Other FunctionsThinking About Passing Functions: max, finder, and bestTightening it up a bitMore Thinking About Passing Functions: repeat, repeatedly, and iterateUntilUse functions, not valuesI said, “Use functions, not values”Functions That Return Other FunctionsCapturing Arguments to Higher-Order FunctionsCapturing Variables for Great GoodTake care when mutating valuesA Function to Guard Against Nonexistence: fnullPutting It All Together: Object ValidatorsSummary