Limit Array Size

Let's say I have an array with data elements, in this example numbers, like this: var a = [432, 238, 122, 883, 983]; And I want to limit the array, so that everytime I add an elem

Solution 1:

Just to add another possible alternative:

a = [x, ...a.slice(0, 6)];

Even though I would personally choose Nina Scholz's solution (with a "better" condition for changing length and for older environments where ES6 is not supported)

References:

• Spread operator

Solution 2:

Just adjust the length property after pushing.

functionadd(x) {
    a.unshift(x);
    a.length = a.length < 7 ? a.length : 7;
}

The cleanes way is to check before

functionadd(x) {
    a.unshift(x);
    if (a.length > 7) {
        a.length = 7;
    }
}

Solution 3:

You can check the length of array when adding and Shift it (remove the first element) if the length has passed:

function add(x) {
    a.push(x);
    if (a.length > 7)
        a.shift();
}

Solution 4:

a=add(188);

function add(x){
  a.push(x);
  return a.slice(1);
}

Solution 5:

You can also use Array.pop. Also if you wish to add a property to array, you can make it generic.

Array.prototype.Limit_push = function(x) {
  this.unshift(x);
  if (this.maxLength !== undefined && this.length > this.maxLength) 
    this.pop();
}

var a = [];
a.maxLength = 7for (var i = 0; i < 10; i++) {
  a.Limit_push(i);
  console.log(a)
}

var b = [];
for (var i = 0; i < 10; i++) {
  b.Limit_push(i);
  console.log(b)
}