slice-vs-splice.js

//// SLICE ////
// first we need an object
x = [1, 2, 3]

// slicing gets a new value, without modifying the old one
x.slice(0, 2) == [1, 2] // true
x == [1, 2, 3] // true

// so we can call it multiple times and x is never mutated
x.slice(0, 2)
x == [1, 2, 3]


//// SPLICE ////
// splice modifies things... so to remove the last element:
x.splice(2, 1) == [3] // true
x == [1, 2] // true

// and calling splice again yields a different value
x.splice(2, 1) == [] // true
x == [1, 2] // true