Populate 2nd dropdown based on selection from 1st dropdown in React.Js

Question

I am learning react and struggling to get a second dropdown to populate based on which option is clicked from first dropdown.

I have included my code below.

I

Answer 1

Some things to look at:

The syntax in your call to setState in your onClick event handler looks incorrect.

You also make try to reference this.state.selected in your .filter condition without the path to the variable (this.state)

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Suggested solution(s):

// The .setState method expects an object to be passed to it rather
// than an expression that mutates the state directly

// Pass it an object containing the properties you want to change,
// ensure your use colon (':') rather than equals sign ('=') to set property:



// In the  tag,
// you need to refer to the selected property in it as this.state.selected:

// Don't forget the closing select tag, it's missing from your snippet

{
  this.state.params
    .filter(tableName => (tableName === this.state.selected))
    .map(columns => columns.map(col => {col}))
}