CHAPTER 7 Ensuring Correct Use of Partial Function Application

WHAT’S IN THIS CHAPTER?            

  • Unit-testing a partial function application
  • Adding a partial function application to an existing object with an aspect
  • Distinguishing between a partial function application and currying

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Occasionally, you will use a function that has several arguments, but some of those arguments will always have the same values. Rather than supplying those values over and over again, it can be convenient to create a new function that wraps the original, supplying the constant arguments and exposing the rest. This technique is called partial function application.

Because you build on a known-good function, the new function is exceptionally easy to unit-test, making it a true friend on the road to reliable JavaScript.

UNIT-TESTING A PARTIAL FUNCTION APPLICATION

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