javascript - Random number, which is not equal to the previous number

Question

I need to get random number, but it should not be equal to the previous number. Here is my piece of the code. But it doesn't work.

function getNumber(){
  var min = 0;
  var max = 4;
  var i;
  i = Math.floor(Math.random() * (max - min)) + min;
  if (i=== i) {
    i = Math.floor(Math.random() * (max - min)) + min;
  }
  return i;
};

console.log(getNumber());

Answer 1

This answer presents three attempts

1. A simple version with a property of the function getNumber, last, which stores the last random value.

2. A version which uses a closure over the min and max values with raising an exception if max is smaller than min.

3. A version which combines the closure and the idea of keeping all random values and use it as it seems appropriate.

---

One

You could use a property of getNumber to store the last number and use a do ... while loop.

function getNumber() {
    var min = 0,
        max = 4,
        random;

    do {
        random = Math.floor(Math.random() * (max - min)) + min;
    } while (random === getNumber.last);
    getNumber.last = random;
    return random;
};

var i;
for (i = 0; i < 100; i++) {
    console.log(getNumber());
}

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