Calling a JSON Value by giving the key as variable?

Question

I want to call a JSON value by giving the key via a variable.

Given if (data[airplane].RunwayThreshold !== undefined){}

Can I make RunwayThreshold a variable?

Answer 1

You can chain bracket access:

data[airplane][RunwayThreshold]

although you may want to check for undefined values along the chain.

Because access is left-associative, that becomes:

(data[airplane])[RunwayThreshold]

and allows you to drill down into objects.