TypeScript - How to check if object exist before assign to variable in one statement?

Question

How to rewrite this in one statement:

if (foo.bar !== undefined) {
    const bee = foo.bar
}

I know there is the answer somewhere already but I can't find the right question in my mind.

What do you want to happen if it's undefined? This code would let you have anything using the variable be out of scope and not use it, but trying to put this in one statement could cause type or runtime errors. — Nicky McCurdy
– Nicky McCurdy, Commented Jul 11, 2020 at 12:38

Karol Majewski · Accepted Answer · 2020-07-11 12:45:48Z

2

If you have some sort of fallback value, you can use the nullish coalescing operator:

const bee = foo.bar ?? fallbackValue;

answered Jul 11, 2020 at 12:45

Karol Majewski

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Comments

vijaykumar · Accepted Answer · 2020-07-11 12:55:32Z

0

You can try loadash npm package. But, under the hood, it does a similar check.

_.get(object, path, [defaultValue])

const bee = _.get('foo', 'bar', 'default');
const bee = _.get('foo', 'bar');

answered Jul 11, 2020 at 12:55

vijaykumar

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