Accessing object properties in Type script

Question

Hi there,

 

I have an object as follows

 

"ObjectName": "{\"property1\":true,\"property2\":\"computers\",\"property3\":\"10\\/07\\/2018  

                           14:04\",\"property4\":25,\"property5\":\"-1\"}";

 

I wan't to access property1, property2, property3, property4 values.

 

Can anyone tell me how can I acheive this in Angular6 type script class.

 

I tried  ObjectName.property1and ObjectName['property1'] both does not work.

 

Thank You