5 ms·

Whoa didn't know about deno repl. This is awesome. Happy 1.7 gs!

benatkin 3y ago
Thanks! You can paste this into deno repl and watch the seconds count up :) for (const [s, d] of (function*() { while (true) { const m=new Date().valueOf(), s=Math.ceil((m+10)/1000); yield [s, s*1000-m] } })()) { await new Promise(r => { setTimeout(()=>r(), d) }); console.log(s) }
- deleted 3y ago
  [deleted]
- lakpan 3y ago
  Is that like a reverse codegolf? setInterval(() => console.log(Math.ceil(Date.now()/1000)), 1000);0 This could be 0.999s late, but seems good enough for REPL usage
  - benatkin 3y ago
    It doesn't just handle the gap but when the first one sends. Suit yourself, though.
- chrismorgan 3y ago
  That seems rather convoluted. The generator function is gratuitous, and the promise stuff is unfortunately verbose (pity there’s no async version of setTimeout built in). I’d write it with a recursive function, this way: function t(){let m=Date.now(),s=Math.ceil((m+10)/1000);setTimeout(()=>{console.log(s);t()},s*1000-m)}t() That maintains the accuracy, but frankly just a 1000ms interval will probably be good enough in most cases, though it’ll drift all over the second (e.g. it loses about a millisecond each tick on my machine under Node), and it’s certainly much simpler to reason about.
  - benatkin 3y ago
    I mixed up two things I was trying to do. I was writing an async generator and making it so inside the loop it could decide what to do with the delay. That way you could add a half tick if you wanted. :) But here's how I would rewrite it: async function* tickSeconds() { while (true) { const m = new Date().valueOf() const s = Math.ceil((m + 10) / 1000) await new Promise((resolve, _) => { setTimeout(() => resolve(), s * 1000 - m) }) yield s } } for await (const s of tickSeconds()) { console.log(s) } I prefer to inline some obvious stuff that is missing than do a paradigm shift to using callbacks or build up an ad hoc library of misc functions.
    - chrismorgan 3y ago
      Still not convinced the generatorness is worthwhile; I’d split out the Promise/setTimeout dance into a `sleep(ms)` or `sleepUntil(date)` function before replacing a simple while loop that logs with a infinite generator and for loop that logs. But certainly if you were scaling it up further you’d want to head in this general direction.

Thanks! You can paste this into deno repl and watch the seconds count up :) for (const [s, d] of (function*() { while (true) { const m=new Date().valueOf(), s=Math.ceil((m+10)/1000); yield [s, s*1000-m] } })()) { await new Promise(r => { setTimeout(()=>r(), d) }); console.log(s) }

deleted 3y ago
[deleted]
lakpan 3y ago
Is that like a reverse codegolf? setInterval(() => console.log(Math.ceil(Date.now()/1000)), 1000);0 This could be 0.999s late, but seems good enough for REPL usage
- benatkin 3y ago
  It doesn't just handle the gap but when the first one sends. Suit yourself, though.
chrismorgan 3y ago
That seems rather convoluted. The generator function is gratuitous, and the promise stuff is unfortunately verbose (pity there’s no async version of setTimeout built in). I’d write it with a recursive function, this way: function t(){let m=Date.now(),s=Math.ceil((m+10)/1000);setTimeout(()=>{console.log(s);t()},s*1000-m)}t() That maintains the accuracy, but frankly just a 1000ms interval will probably be good enough in most cases, though it’ll drift all over the second (e.g. it loses about a millisecond each tick on my machine under Node), and it’s certainly much simpler to reason about.
- benatkin 3y ago
  I mixed up two things I was trying to do. I was writing an async generator and making it so inside the loop it could decide what to do with the delay. That way you could add a half tick if you wanted. :) But here's how I would rewrite it: async function* tickSeconds() { while (true) { const m = new Date().valueOf() const s = Math.ceil((m + 10) / 1000) await new Promise((resolve, _) => { setTimeout(() => resolve(), s * 1000 - m) }) yield s } } for await (const s of tickSeconds()) { console.log(s) } I prefer to inline some obvious stuff that is missing than do a paradigm shift to using callbacks or build up an ad hoc library of misc functions.
  - chrismorgan 3y ago
    Still not convinced the generatorness is worthwhile; I’d split out the Promise/setTimeout dance into a `sleep(ms)` or `sleepUntil(date)` function before replacing a simple while loop that logs with a infinite generator and for loop that logs. But certainly if you were scaling it up further you’d want to head in this general direction.