React JS setState({dict : dict }) - dictionary

Question

I wonder if this is the correct solution to update the state with two dictionares
var PopulationCityView = React.createClass({
getInitialState: function() {
return {
prod_diff : {'wheat':0,'meat':0,'fish':0,'bread':0,'fruit':0,'wine':0,'beer':0,'wool':0,'cloth':0,'leather':0,'paper':0,'ceramics':0,'furniture':0,'glass':0}
};
},
componentWillMount: function() {
this.prod_diff = {'wheat':0,'meat':0,'fish':0,'bread':0,'fruit':0,'wine':0,'beer':0,'wool':0,'cloth':0,'leather':0,'paper':0,'ceramics':0,'furniture':0,'glass':0};
},
handleM: function(res,child_new_res_diff){
var new_prod_diff = this.prod_diff;
new_prod_diff[res] = child_new_res_diff;
this.setState({prod_diff:new_prod_diff});
},
render: function(){
........
if anyone knows of a better and faster solution would ask for a hint...

Answer 1

Much safer and more efficient way is to keep your state as simple object with primitive values:
var PopulationCityView = React.createClass({
getInitialState: function() {
return {
wheat: 0,
meat: 0,
fish: 0,
};
},
handleM: function(res,child_new_res_diff){
var new_state = {};
new_state[res] = child_new_res_diff;
this.setState(new_state);
},
render: function() { /* your render code */ }
});
If you really have to store your values in nested object you have to remember to clone nested object before modifying it:
var PopulationCityView = React.createClass({
getInitialState: function() {
return {
prod_diff: { wheat: 0, meat: 0, fish: 0 }
};
},
handleM: function(res,child_new_res_diff){
var new_prod_diff = _.clone(this.state.prod_diff);
new_prod_diff[res] = child_new_res_diff;
this.setState({ prod_diff: new_prod_diff });
},
render: function() { /* your render code */ }
});
I've made your initial state a little smaller to simplify code examples.
Also consider using React Immutability Helpers which makes operating on nested objects inside state safer.

Answer 2

I forgot to add that handleM function arguments are sent by the child.
In my solution it does not work smoothly (slider that adjusts the prod_diff jams), the same effect is when I apply the solution #daniula
Now I have decided to make use of CortexJS and everything runs smoothly
I would ask to correct me if I used this library incorrectly:
PARENT
var PopulationCityView = React.createClass({
getInitialState: function() {
return {
prod_diff_C : new Cortex({'wheat':0,'meat':0,'fish':0,'bread':0,'fruit':0,'wine':0,'beer':0,'wool':0,'cloth':0,'leather':0,'paper':0,'ceramics':0,'furniture':0,'glass':0}),
};
},
componentWillUnmount: function() {
delete this.state.prod_diff_C;
},
componentDidMount: function(){
var that = this;
this.state.prod_diff_C.on("update",function (updatedRes) {that.setState({prod_diff_C: updatedRes});});
},
// handleM: function(res,child_new_res_diff){
// var new_prod_diff = this.prod_diff;
// new_prod_diff[res] = -child_new_res_diff;
// this.setState(new_prod_diff);
// },
render: function(){
var foods = {}, goods = {};
for(var g = 0; g< this.goods.length; g++){
R = this.goods[g];
goods[R] = <div style={{display:"inline-block"}}>
<CHILD_1 res_par={this.props.data.res_uses[R]} res={R} prod_diff_cortex={this.state.prod_diff_C}/>
<SLIDER prod_diff_cortex={this.state.prod_diff_C} res={R} res_have={this.props.data.res_uses[R][0]} res_need={this.props.data.res_uses[R][1]} />
</div>
}
}
return ( .... )
}
})
CHILD_1
var CHILD_1 = React.createClass({
render: function(){
var val = this.props.res_par[3] + this.props.prod_diff_cortex[this.props.res].getValue()
return (
<div className='population-production-upkeep'>
{val}
</div>
)
}
})
SLIDER
var SLIDER= React.createClass({
......
handleMouseDown: function(event){
var start_val = this.props.res_have + this.props.prod_diff_cortex[this.props.res].getValue()
this.val_start = start_val;
this.res_diff_start = this.props.prod_diff_cortex[this.props.res].getValue()
this.touched = 1;
this.pos_start_x = event.screenX;
this.prev_pos_x = this.width_step * start_val;
event.stopPropagation();
event.preventDefault();
},
handleMouseMove: function(event){
if(this.touched) {
var x_diff = event.screenX - this.pos_start_x ;
var x = this.prev_pos_x + x_diff;
if (x < 0) x = 0;
if (x > this.state.max_pos_x) x = this.state.max_pos_x;
var stor = Math.round(x* 100 / this.width_step ) / 100
var new_res_diff = this.res_diff_start + stor - this.val_start;
this.props.prod_diff_cortex[this.props.res].set(new_res_diff)
}
},
......
render: function() {
var val = Math.round((this.props.res_have+this.props.prod_diff_cortex[this.props.res].getValue())*100)/100;
return (
..../* slider render */
);
}
});