Why do I get SyntaxError: Assigning to rvalue?

I have a map() and I want to pass two parameters:

1. a string
2. a function

Example code:

{ values.map((workflow, totalWorkflow()) => { return <WorkflowSingle key={ workflow } workflow={ workflow } /> }) }

Why do I get this error: SyntaxError: Assigning to rvalue

4 Answers

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 } } 

Look at your comparison operator. They are in the wrong direction (=>). Put the equal to sign always at the right and your less or greater than always at the left of your assignment operator(>=)