replace value of a variable using grunt-text-replace

I want to replace the value of a variable which is string in nodejs. I'm using grunt as my task runner and when I run grunt, I want to replace is the value of var a,b,c which is url according to the different task that I run. This is my statement: var a = 'www.xyz.com', var c = 'localhost:4000'

Now what happens is when I run, grunt-text-replace, it replaces the 'a','b','c' instead of replacing the value. Can someone suggest me how to fix this.

via batman