I'm using data in JSON format to be displayed in a table. What is the best approach passing in a prop to only display(or not display) a certain group of columns in a table?
componentDidMount() {
fetch('http://localhost:7000/worldStats')
.then((data) => data.json())
.then((data) => this.setState( { stats: data } ));
}
render(){
return(
// Table..
{this.state.stats.map( (item) => {
// Items..
<td>{item.ID}</td>
<td>{item.CURRENCY}</td>
<td>{item.NAME}</td>
<td>{item.GDP}</td>
<td>{item.POP}</td>
})}
)
Considering that you're rendering a table and all you want to do is toggle which columns to display, I think it makes sense to keep all the logic in a single component. This means there is no need to pass props from one component to then next. Instead, we'll just be utilizing the component state.
Consider the following code:
import React from "react";
class Table extends React.Component {
state = {
stats: [],
indexOfFirstExtendedField: 2,
displayExtendedFields: true
};
componentDidMount() {
const newData = [
{
id: 1,
currency: "USD",
name: "dollars",
gdp: "alot",
pop: "alot"
},
{
id: 2,
currency: "MEX",
name: "pesos",
gdp: "alot",
pop: "alot"
}
];
this.setState({
stats: newData
});
}
toggleDisplay = () => {
this.setState(prevState => {
return {
displayExtendedFields: !prevState.displayExtendedFields
};
});
};
createTableHeaders = () => {
const {
indexOfFirstExtendedField,
stats,
displayExtendedFields
} = this.state;
if (displayExtendedFields) {
return Object.keys(stats[0]).map(key => {
return <th>{key}</th>;
});
} else {
return Object.keys(stats[0])
.filter((key, index, array) => {
return array.indexOf(key) < indexOfFirstExtendedField;
})
.map(key => {
return <th>{key}</th>;
});
}
};
createTableContent = () => {
const {
indexOfFirstExtendedField,
stats,
displayExtendedFields
} = this.state;
if (displayExtendedFields) {
return stats.map(item => {
return (
<tr>
{Object.values(item).map(value => {
return <td>{value}</td>;
})}
</tr>
);
});
} else {
return stats.map(item => {
return (
<tr>
{Object.values(item)
.slice(0, indexOfFirstExtendedField)
.map(value => {
return <td>{value}</td>;
})}
</tr>
);
});
}
};
render() {
const { stats, displayExtendedFields } = this.state;
return (
<div>
<button onClick={this.toggleDisplay}>
{displayExtendedFields ? "Collapse" : "Expand"}
</button>
<table>
{stats.length > 0 && this.createTableHeaders()}
{stats.length > 0 && this.createTableContent()}
</table>
</div>
);
}
}
export default Table;
The main takeaways here is that we are using two additional state-values to help us determine which fields to display, indexOfFirstExtendedField
and displayExtendedFields
. This helps us expand and collapse the columns.
Here's the codesandbox too so you can see it in action: https://codesandbox.io/s/v3062w69v0
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