這是從第2位開始刪除所有元素的程式

var myFish = ['angel', 'clown', 'mandarin', 'sturgeon'];
var removed = myFish.splice(2);
// 運算後的myFish ：["angel", "clown"] 
// 被刪除的元素數組： ["mandarin", "sturgeon"]

但現在我想做的是，利用IP找到檔案中相對應資料並刪除

[{"ID":0,"Name":"XXX","Enable":true,"IP":"XXX.XXX.XXX.01","Port":8080,"Model":"XXX"},//這是一筆
{"ID":0,"Name":"XXX","Enable":true,"IP":"XXX.XXX.XXX.02","Port":8080,"Model":"XXX"},//這是一筆
{"ID":0,"Name":"XXX","Enable":true,"IP":"XXX.XXX.XXX.03","Port":8080,"Model":"XXX"}]//這是一筆

想請問我如果用ajax的方式做(如下)，

$.ajax({
    url: 'test.txt',
    type: 'POST',
    dataType: 'text',
    contentType: 'application/json; charset=utf-8',
    success: function (data) {
    },
    error: function(jqXHR) {
    }
})

因為我沒有任何跟myFish一樣的任何陣列，那麼我上面第一個程式該怎麼改?