Redux 14 challenge: Do not Mutate state about fcc-react-tests-module

[bonham000]

The concat method is an immutable operation, based on how the JS spec is written: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/concat

This is generally acceptable for immutable operations on arrays of data, like the ones described here.

[japickering]

@bonham000 True and I have used concat() before but in the Mozilla dev link you've quoted the data arrays are explicitly documented in the code example so it's obvious that 2 arrays need to be combined together.

In this Redux challenge the learner has no such information about the problem. The answer was passing a todo action into a state.concat() but how would you even know that the todo action is in array format to arrive at the solution to it?

e.g. if you do this:
const immutableReducer = (state = ['Do not mutate state!'], action) => { switch(action.type) { case ADD_TO_DO: console.log(action.todo); return state.concat(action.todo); default: return state; } };

You get this in the console log:
TEST__TO__DO

[bonham000]

@japickering I think you have some valid points here. I just made some updates to the challenge. Take a look and let me know what you think! Thanks for bringing this up.

[japickering]

@bonham000 Thanks Sean that's much clearer. If I do console.log(state.concat(action.payload));
I get the following code..
["Go to the store", "Clean the house", "Cook dinner", "Learn to code", "__TEST__TO__DO__"]

[bonham000]

Great! I'm going to close this now. Please let me know if you find anything else that you think should be improved.