vue-playgound/src/store/modules/distributor/mutations.js

import * as types from '../../types';

export default {
    [types.UPDATE_DISTRIBUTORS]: (state, payload) => {
        Vue.set(state, 'distributors', payload);
    },
    [types.UPDATE_DISTRIBUTOR]: (state, payload) => {
        if (payload.id) {
            state.distributors.forEach(distributor => {
                if (distributor.id === payload.id) {
                    distributor = Object.assign(distributor, payload);
                } 
            });
        }
    }
};