tedbyron / code-golf

My code golf solutions

code-golf

My code golf solutions

JavaScript Code Golf Notes

Operators

• remove whitespace after operators when possible
• bitwise OR |
  • number|0 equivalent to Math.trunc(number)
• bitwise NOT ~
  • sets number to -(number+1), so can be used with functions that return -1 if a 0 return is needed
  • coerces non-numbers to -1
  • use with search() (though match() should be used over search())
• bitwise XOR ^
  • replace != with ^ when comparing integers
• bracket operator []

  Object[m='method'](arguments) // first method/property call
  Object[m](arguments)          // subsequent calls

length of method/property	minimum calls
3	7
4	4
5	3
6	3
7	3
8+	2

• comma ,
  • replace curly braces in conditionals and loops with commas between statements
• power **
  • a**b is equivalent to Math.pow(a,b)
• spread ...
  • saves bytes when no callback is needed

Loops

• for, for in , for of
  • reverse loops to remove expressions

    for (a=0;a<b.length;a++) // before
    for (a=b.length;a--;)    // after

  • [...array] use spread operator when possible

Methods

• template literals instead of parentheses when possible
• isFinite()
  • 1/number to check instead
• isNaN()
  • number^number instead of isNaN(number)
• Math.pow()
  • ** operator
• Math.random()
  • new Date & 1 == Math.random() < .5
  • new Date % 330 == Math.floor(Math.random()*330)
• Math.trunc(), Math.round()
  • |0 bitwise OR instead
• RegExp()
  • eval() instead
• array
  • use coercion ''+array instead of join(',') or join()
  • spread operator instead of forEach() when possible
• string
  • match() instead of search() instead of indexOf() unless regex is longer than string or you need a numeric return
  • slice() is always shorter than substring, can slice(-n) to get the last n elements
  • split() use spread operator when splitting over every element

Variables

• use type specific methods to test type

type	test
array	pop()
function	call()
number	toFixed()
string	big()
textNode	data()

• initialize variables in parameters of functions or loops
• this or self instead of window
• array
  • map() instead of reduce() when possible
  • use elision to put values in certain indices
• boolean
  • !0 for true and !1 for false if you need literal boolean values, or else use 1 and 0
  • !! to change a value to true or ! for false
• function
  • omit parentheses on new calls without arguments
• Infinity
  • 1/0 instead of Infinity
• number
  • +number instead of parsing to coerce to float or integer
  • AeB instead of numbers with many trailing zeros
  • number|0 to cast to integer, equivalent to Math.trunc(number)

Regex

• \b for word boundaries
• \d instead of [0-9]
• \w instead of [A-Za-z0-9_]