Question

I was playing around with JavaScript dates and I’m looking for an explanation pertaining to the last logged array. Why are the numbers 1352589000, 1352589395 different?

Code

var examples = [
    "Fri Jan 16 1970 10:43:09 GMT-0500 (EST)",
    1352589395
];

var text = [
    new Date((examples[0])),
    new Date((examples[1])),
];

var unix = [
    new Date((examples[0])).getTime(),
    new Date((examples[1])).getTime(),
];

console.log(examples);
console.log(text);
console.log(unix);

Output

[
  'Fri Jan 16 1970 10:43:09 GMT-0500 (EST)',
  1352589395
][
  'Fri Jan 16 1970 10:43:09 GMT-0500 (EST)' ,
  'Fri Jan 16 1970 10:43:09 GMT-0500 (EST)' 
][
  1352589000,
  1352589395
]

Answer 1

The numbers are in milliseconds. The difference between them is 395, which is less than half a second. The string format you’re using only goes down to the second, and so its milliseconds portion is 0, but the number you’re parsing includes the milliseconds (all 395 of them).