var o = {hello:'world', greetings: ['one', 'two', 'three']};
undefined

// regular, difficult to read for large objects
JSON.stringify(o);
"{"hello":"world","greetings":["one","two","three"]}"

// presto!
JSON.stringify(o, '', '  ');
"{
  "hello": "world",
  "greetings": [
    "one",
    "two",
    "three"
  ]
}"