如何避免包含相同对象的两个数组的反射？

Question

I'm having two arrays of same objects,

var callHistory = [{"CallId":1,"Note":"abcdefghijklmnop"}, {"CallId":2,"Note":"123343"}, {"CallId":3,"Note":"abc123"}];
var tempHistory = [{"CallId":1,"Note":"abcdefghijklmnop"}, {"CallId":2,"Note":"123343"}, {"CallId":3,"Note":"abc123"}];

for(var i = 0; i < tempHistory .length; i++)
{
    var callNote = tempHistory [i]["Note"];
    if(callNote.length > 6)
    {
        callNote = callNote.slice(0, 5);
        tempHistory [i]["Note"] = callNote;
    }
}

Here i'm changing the Note value of tempHistory array of index 0, but i'm getting the reflected response on callHistory also.

After the end of for loop.

callHistory = [{"CallId":1,"Note":"abcdef"}, {"CallId":2,"Note":"123343"}, {"CallId":3,"Note":"abc123"}];
tempHistory = [{"CallId":1,"Note":"abcdef"}, {"CallId":2,"Note":"123343"}, {"CallId":3,"Note":"abc123"}];

How it is getting reflected and is there anyway to stop those kind reflection.

Answer 1

You need to clone the object How do I correctly clone a JavaScript object? :

 function clone(obj) { if (null == obj || "object" != typeof obj) return obj; var copy = obj.constructor(); for (var attr in obj) { if (obj.hasOwnProperty(attr)) copy[attr] = obj[attr]; } return copy; } var callHistory = [{"CallId":1,"Note":"abcdefghijklmnop"}, {"CallId":2,"Note":"123343"}, {"CallId":3,"Note":"abc123"}]; var tempHistory = [{"CallId":1,"Note":"abcdefghijklmnop"}, {"CallId":2,"Note":"123343"}, {"CallId":3,"Note":"abc123"}]; for(var i = 0; i < tempHistory .length; i++) { var callNote = clone(tempHistory [i]["Note"]); if(callNote.length > 6) { callNote = callNote.slice(0, 5); tempHistory [i]["Note"] = callNote; } } console.log(callHistory); console.log(tempHistory);