Write additional selector transformers

[jimbol]

.select(...inputSelectors, resultFunc): *

• Operates on anything
• Accepts 0 to n inputSelectors
• Requires a resultFunc as the last argument
  • resultFunc receives selector outputs as arguments, in order
  • resultFunc receives previous output as the last argument
• returns any value

.map(...inputSelectors, resultFunc): *

• Operates on an array
• Accepts 0 to n inputSelectors
• Requires a resultFunc as the last argument
  • resultFunc receives selector outputs as arguments, in order
  • resultFunc gets called for each item in the previous output
  • resultFunc is expected to return true or false
• returns any value

.reduce(...inputSelectors, resultFunc, accumulator): *

• Operates on an array
• Accepts 0 to n inputSelectors
• Requires a resultFunc as the second to last argument
  • resultFunc receives selector outputs as arguments, in order
  • resultFunc gets called for each item in the previous output
  • resultFunc is expected to return true or false
• returns any value