1. “Hey Underscore,
You’re doing it wrong”
You’re doing it wrong”

2. I <3 _

3. So what’s wrong then?

5. Agenda
• Currying
• Composition
• Functors
• Random stuff

6. Currying

7. Curried Function
“A function that will return a new function until it
receives all it’s arguments”

11. ...weird

12. Wu.js to the rescue!
(well, one function at least)
(well, one function at least)

15. not weird

24. Example

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29. underscore’s api
prevents you from
currying

31. Currying
• Make generic functions - data is gone
• Build new functions by applying args
• Much more concise definitions
• Make types “line up” for composition

32. Composition

41. Category Theory
“The mathematical theory of transforming values
and crap”
*inaccurate definition

45. Example

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50. underscore
promotes chain as
the function of
choice.

52. Composition
• Build new functions from other functions
• Helps build generic programs w/o args
• Extremely high level coding
• Mathematically backed

53. Functors

68. Example

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72. underscore explicitly
prevents extending
map

74. s
• Change behavior without altering function
open/closed principle
• Not just map - reduce, compose, etc
• Intuition and “non proprietary” api
• Free formulas
• Dynamic type safety?

75. In conclusion