How to get a random list item in JavaScript

Question

I am using discord.py to make a Discord bot that gives you a complement every 24 hours. To test, I set the timer to 1 second. The code I made looked like this:

const Discord = require('discord.js')
const client = new Discord.Client()

const complements = [
    ...
]

client.once('ready', () => {
    console.log('Logged in!');
    client.user.setActivity("with nice complements.")
    setInterval(console.log,1000,complements[Math.floor(Math.random() * (complements.length - 1))]);
});

However, this just returns the same complement every time. Is there any ways it can choose a random complement?

Is that discord.py or discord.js?

Hao C.
– Hao C.

2020-05-21 19:31:58 +00:00
Commented May 21, 2020 at 19:31 — Hao C.
– Hao C., Commented May 21, 2020 at 19:31
@Pepe_Worm discord.js

DaInfLoop
– DaInfLoop

2020-05-21 19:32:55 +00:00
Commented May 21, 2020 at 19:32 — DaInfLoop
– DaInfLoop, Commented May 21, 2020 at 19:32

t.niese · Accepted Answer · 2020-05-21 19:36:51Z

2

The parameters you pass to setInterval are evaluated at the time when you pass them to the setInterval function not at each execution of it.

So this: setInterval(console.log,1000,complements[Math.floor(Math.random() * (complements.length - 1))]);

is equal to:

let complement = complements[Math.floor(Math.random() * (complements.length - 1))];
setInterval(console.log,1000, complement);

You need to pass a callbnack function to setInterval that is executed, and move you random access there.

setInterval(() => {
   console.log(complements[Math.floor(Math.random() * (complements.length - 1))])
}, 1000)

answered May 21, 2020 at 19:36

t.niese

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Comments

demaroar · Accepted Answer · 2020-05-21 19:36:38Z

0

Try to use setInterval like this:

setInterval(() => {
  const value = complements[Math.floor(Math.random() * (complements.length - 1))];
  console.log(value);
},1000);

answered May 21, 2020 at 19:36

demaroar

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Comments

Dima Vak · Accepted Answer · 2020-05-21 19:42:04Z

0

Problem is setInterval. He call the function with the same result. Try it and check console

let x = setInterval(console.log(Math.random()),1000,);

let num = 0;
let y = setInterval(() => {
console.log(num)
num += 1
}
,1000,);

answered May 21, 2020 at 19:42

Dima Vak

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Comments

Robin Zigmond · Accepted Answer · 2020-05-21 19:58:02Z

0

Rather than pass a fixed argument to console.log in each iteration (I'd actually never seen setInterval called with more than 2 parameters before and had to look up what it meant :-)), pass a function which, when called, generates a new random value and passes that to console.log:

 setInterval(() => {
    const complement = complements[Math.floor(Math.random() * (complements.length - 1)) ] ;
    console.log(complement);
 }, 1000)

edited May 21, 2020 at 19:58

answered May 21, 2020 at 19:37

Robin Zigmond

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