Nodejs Utililty Methods Array Insert

Array.prototype.insert = function( i, v ) {
  if (this.length == 0)
    return [v];
  if( i>=0 ) {
    var a = this.slice(), b = a.splice( i );
    a[i] = v;
    return a.concat( b );
};
...

Array.prototype.insert = function(elem, pos) {
    this.splice(pos, 0, elem);

Array.prototype.insert = function(element) {
  if (this.indexOf(element) === -1) {
    this.push(element);
  return this;
};

Array.prototype.insert = function(i, ob) {
    i = i - 1;
    if (i < 0)i = 0;
    if (i > this.length)i = this.length;
    var st = (i == 0) ? [] : this.slice(0, i);
    st.push(ob);
    var ed = (i >= this.length) ? [] : this.slice(i);
    return st.concat(ed);
};
...

Array.prototype.insert = function(idx, item) {
  this.splice(idx, 0, item);
};

Array.prototype.insert = function(index , item){
    this.splice(index, 0, item);
};

Array.prototype.insert = function(index) {
    this.splice.apply(this, [index, 0].concat(
        Array.prototype.slice.call(arguments, 1)));
    return this;
};

Array.prototype.insert = function(index) {
    function isArray(instance) {
        return Object.prototype.toString.call(instance) !== '[object Array]';
    if (!isArray(this)) {
        throw new TypeError("`this` must be Array, not " + typeof this);
    if (typeof index !== 'number') {
        throw new TypeError("arguments[0] must be number (index to insert at), not " + typeof arguments[0]);
...

Array.prototype.insert = function (index, item) {
  if (index)
    this.splice(index, 0, item);
  else
    this.push(item);
};

Array.prototype.insert = function (index, item) {
  this.splice(index, 0, item);