var rand image without repeating

Question

I wish I wouldn't repeat the images until I send all the photos possible, is there a way?

const discord = require('discord.js');
const image = require('../image.json')
var rand = image[Math.floor(Math.random() * image.length)];
exports.run = async (client, message, args) => {

         const embed = new Discord.MessageEmbed()
        .setColor('RED')
        .setDescription(`Dog`)
        .setImage(rand)
         await message.channel.send(embed);
}

Answer 1

As I mentioned in my comment, instead of choosing a random item from a set and then trying to inspect whether you've already selected that random item, take the full set and shuffle it. Then you can just iterate over the shuffled set instead of trying to pick a random item that you hope doesn't collide with an item you've previously selected.

Looks something like this:

let arrayLen = 25; //assume you have a list of 25 items
let imageList = [...Array(arrayLen).keys()]; // makes an array of 0 thru arrayLen
console.log("Before: ", imageList);
let shuffledImages = shuffle(imageList); // <-- you'll want to iterate over shuffled images
console.log("After: ", shuffledImages); 

/**
 * Add loop code that you had been using to generate a new random, 
 * but just iterate over `shuffledImages` array instead
 */

// This is the Fisher-Yates shuffle algorithm
function shuffle(array) {
  var m = array.length, t, i;

  // While there remain elements to shuffle…
  while (m) {

    // Pick a remaining element…
    i = Math.floor(Math.random() * m--);

    // And swap it with the current element.
    t = array[m];
    array[m] = array[i];
    array[i] = t;
  }

  return array;
}

Answer 2

It looks like you want to be able to always get images even after exhausting the list, but that you don't want to have duplicates until you've gone through the entire array.

Here is a possible implementation using a generator function and the Fisher-Yates shuffle:

// shuffle a copy of the array
function shuffled(arr) {
  const copy = arr.slice();
  for (let i = arr.length - 1; i > 0; i--) {
    const j = Math.floor(Math.random() * (i + 1));
    const temp = copy[i];
    copy[i] = copy[j];
    copy[j] = temp;
  }
  return copy;
}

// give next element in array; if exhausted, shuffle and repeat
function* imageGenerator(arr) {
  while (true) {
    for (const e of shuffled(arr)) {
      yield e;
    }
  }
}

// proof of concept; [1, 2, 3] would be replaced with your array
const images = imageGenerator([1, 2, 3]);
for (let i = 0; i < 5; i++) {
  // get next image
  console.log(images.next().value);
}

.as-console-wrapper {min-height: 100%;}

Here's how it might look in your case:

const discord = require('discord.js');
const image = require('../image.json')

// shuffle a copy of the array
function shuffled(arr) {
  const copy = arr.slice();
  for (let i = arr.length - 1; i > 0; i--) {
    const j = Math.floor(Math.random() * (i + 1));
    const temp = copy[i];
    copy[i] = copy[j];
    copy[j] = temp;
  }
  return copy;
}

// give next element in array; if exhausted, shuffle and repeat
function* imageGenerator(arr) {
  while (true) {
    for (const e of shuffled(arr)) {
      yield e;
    }
  }
}

const images = imageGenerator(image);

exports.run = async (client, message, args) => {
  const embed = new Discord.MessageEmbed()
    .setColor('RED')
    .setDescription(`Dog`)
    .setImage(images.next().value)
    await message.channel.send(embed);
}