how to use the isset function from the lodash library in typescript

The isset function is not a part of the Lodash library. However, Lodash provides an _.get function that can be used to check if a property exists on an object. Here's how you can use it in TypeScript:

index.ts
import * as _ from 'lodash';

const myObject = {
  foo: {
    bar: 'baz'
  }
};

if (_.get(myObject, 'foo.bar') !== undefined) {
  console.log('foo.bar exists');
} else {
  console.log('foo.bar does not exist');
}
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In the example above, _.get is used to check if the foo.bar property exists on the myObject object. If it does, the first branch of the if statement is executed, and if it doesn't, the second branch is executed. The undefined value is returned by _.get if the property does not exist on the object.

Note that _.get can also be used to retrieve nested property values. If the property you are checking is nested, you can use a dot-separated string to represent the full path to the property.