Nodejs Utililty Methods Array Push If Not Exist

Array.prototype.pushIfNotExist = function(element, comparer) { 
    if (!this.inArray(comparer)) {
        this.push(element);
};

Array.prototype.pushIfNotExist = function(element, comparer) { 
    if (!this.inArray(comparer)) {
        this.push(element);
};

Array.prototype.pushIfNotExist = function(element, comparer) { 
    if (!this.inArray(comparer)) {
        this.push(element);
}; 
function arrayObjectIndexOf(myArray, property, searchTerm) {
    for(var i = 0, len = myArray.length; i < len; i++) {
        if (myArray[i][property] === searchTerm) return i;
    return -1;

Array.prototype.pushIfNotExist = function(element, comparer) { 
    if (!this.inArray(comparer)) {
        this.push(element); 
        return true;
    return false;
}; 
function arrayObjectIndexOf(myArray, property, searchTerm) {
    for(var i = 0, len = myArray.length; i < len; i++) {
...

Array.prototype.pushIfNotExist = function (item) {
    if (item == null)
        return;
    var exist = false;
    for (var i = 0; i < this.length; i++) {
        if (this[i] == item) {
            exist = true;
            break;
    if (!exist)
        this.push(item);
};

Array.prototype.pushIfNotExist = function(item) {
  if (!this.inArray(item)) {
    this.push(item);
};

Array.prototype.pushIfNotPresent = function (pValue){
    var lArray = this || [];
    if (lArray.indexOf(pValue) == -1){
        lArray.push(pValue);
        return true;
    return false;