/ten-useful-functions

Write ten functions that are useful in some way, and demonstrate their use.

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Ten Useful Functions

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Write ten functions that are useful in some way, and demonstrate their use both by calling them directly and by passing them to Array iteration methods like .map(), .forEach(), .filter(), .reduce(), .every().

Description

The only way to write better code is to write more code. In this exercise, you'll write at minimum ten different functions and use them in some way.

Here are a few ideas:

Strings

  • upperCase(string): Return string in all CAPITAL LETTERS.
  • lowerCase(string): Return string in all lowercase letters.
  • capitalize(string): Return string with the first letter Capitalized.
  • sentenceCase: Return string with the first letter capitalized, and convert the rest of the string to lowercase.
  • titleCase(string): Return string with Every Word Capitalized.
  • camelCase(string): Return string converted to camelCase by capitalizing all words but the first, and removing all non-word characters (everything but a–z, A–Z, 0–9, and _ (underscore)). For example: "Bermuda Love Triangle is Awesome!!" would be converted to "bermudaLoveTriangleIsAwesome".
  • snakeCase(string): Return string converted to "snake_case": separate out all "camelCased" words, lowercase all characters, and replace non-word characters (or multiple non-word characters) with a single underscore. Remove beginning or trailing underscores.
  • kebobCase(string): Return string converted to "snake_case": separate out all "camelCased" words, lowercase all characters, and replace non-word characters (or multiple non-word characters) with a hyphen (-). Remove beginning or trailing underscores.

Number Utilities

  • range(start, end, step): Return an Array of numbers (positive and/or negative) progressing from start up to, but not including, end. Increment by step if provided, or 1 if not. If end is less than start, a zero-length range is created unless a negative step is specified.
  • largest: Return the greater of two numbers
  • smallest: Return the smaller of two numbers

Functional Utilities

  • constant(value): Return a function that ALWAYS returns a specific value
  • is(value): Return a function that returns true when passed something strictly equal to value, and false when passed something other than value.
  • greaterThan(n): Return a function that returns true when passed a number greater than value, and false when passed something equal to or smaller than value.
  • greaterThanOrEqualTo(n): Return a function that returns true when passed a number greater than or equal to value, and false when passed something smaller than value.
  • lessThan(n): Return a function that returns true when passed a number less than value, and false when passed something equal to or greater than value.
  • lessThanOrEqualTo(n): Return a function that returns true when passed a number less or equal to value, and false when passed something greater than value.
  • noop(): Define a function that takes no parameters, has no method body, and returns nothing.
  • compose(fn1, fn2[, ...fnN]): Return a new function such that compose(fn1, fn2)(1, 2) is the same as fn1(fn2(1, 2)).
  • pipe(fn1[, fn1[, ...fnN]): Return a function that, when executed, passes its arguments