The OP has reference errors as bisData1 is not declared or assigned a value.
Assuming that is fixed and an array is assigned to bisData1, the assigning the result of bisData1.sort to bisData creates two references to the same array.
As noted in comments, you should not use Math.abs as sort requires a result that is a negative, zero or positive number.
An incorrect property name has been used when trying to reference the "Created At" property.
All code required to reproduce the issue should be posted in the question as text, not as images.
The linked code image has syntax errors. What you might have meant is something like:
let data = [
{"Created At": "Mon Jul 04 2019 13:05:21 GMT-0000 (GMT)","status":"send"},
{"Created At": "Mon Jul 08 2019 13:06:02 GMT-0000 (GMT)","status":"send"},
{"Created At": "Mon Jul 08 2019 14:07:59 GMT-0000 (GMT)","status":"send"},
{"Created At": "Mon Jul 05 2019 13:27:17 GMT-0000 (GMT)","status":"send"},
{"Created At": "Mon Jul 05 2019 13:27:17 GMT-0000 (GMT)","status":"send"}];
data.sort(function(a,b){return new Date(a['Created At']) - new Date(b['Created At'])});
console.log(data);
Which works as expected and sorts the data array.
In regard to parsing strings with the built–in parser, seeWhy does Date.parse give incorrect results? and MDN: Date.parse.