对象中键的打字稿名称

Question

Suppose we have object like this:

foo = {
   "currency": "dollar"
}

Is it possible to check if value of object exists and is equal to dollar? For example:

const bar = currency;

So how can we pass the value of bar to foo path? Or use any syntax that should work as $bar? I don't want to pass $bar as a path name but a value of bar as a path.

foo.$bar? true: false
in result  foo.currency === true or false

Or even is it possible to have another object like:

anotherobject.anotherpath.$(getKey(foo))

to get object like anotherobject.anotherpath.currency?
Hope it's clear enough to understand

Answer 1

Objects act a bit like arrays in that you can access values stored in a certain index using the bracket notation - but in this case, using the key or field in place of the numeric index.

So you can:

const foo = { "currency": "dollar" };
const bar = "currency"

if (foo[bar] == "dollar") { /* do something */ }

If you want to check if the 'bar' property exists in the foo object, you can also do:

const foo = { "currency": "dollar" };
const bar = "currency"

// will check if foo.bar exists
if (foo.hasOwnProperty(bar)) {/* do something */}

Answer 2

var foo = {
   "currency": "dollar"
};
var bar = "currency";

Check if the key exists:

if (foo[bar])

Or:

if (foo.hasOwnProperty(bar))

Check if property has the right value

if (foo[bar] == "dollar")

Answer 3

You can use Object.values() :

example is below:

var foo = {
   "currency": "dollar"
};
var bar = "currency";


console.log(Object.values(foo).indexOf(bar) >= 0); //false
console.log(Object.keys(foo).indexOf(bar) >= 0); //true