How to change element in reducer?

Question

React

My state is displayed in this form prntscr.com/cc1tmc . I can’t figure out how to change the data correctly, for example, here prntscr.com/cc1tx7 . Given that the first key (in this case 0) is in my $first variable, and the second key (in this case also 0) is in my $last variable. In the reducer itself, I get the desired element like this state[action.key1][action.key2] . but I don’t know how to change it correctly in state

Answer 1

DEMO .

const initalState = {
  foo: 'bar',
  baz: 'pew',
  structure: [
    ['', ''],
    ['', ''],
  ],
};

const reducer = (state, action) => {
  switch (action.type) {
    case 'ADD_INPUT':
      return {
        ...state,
        structure: state.structure.map((v1, k1) => {
          if (k1 === action.first) {
            return v1.map((v2, k2) => {
              if (k2 === action.second) {
                return action.value;
              } else {
                return v2;
              }
            });
          } else {
            return v1;
          }
        }),
      };
      break;

    default:
      return state;
  }
};

const newState = reducer(initalState, {
  type: 'ADD_INPUT',
  first: 0,
  last: 0,
  value: 'foo',
});

console.log(initalState);
console.log(newState);