Why do I get SyntaxError: Assigning to rvalue?
You get rvalue error, when you use = instead of == in a condition checking block.
If your map function is the Array.prototype.map function, you passed wrong parameters to the function, map accepts callback and second optional parameter, like this:
arr.map(callback[, thisArg])
For your case:
values.map(function(x) { return <WorkflowSingle key = { x.workflow } workflow = { x.workflow } />});
For those who came here getting this eslint error in a new project with completely valid code - you need to provide the config to eslint, e.g.:
{ "parserOptions": { "ecmaVersion": 2017 }, "env": { "es6": true }}