how to use the stubfalse function from lodash in javascript

The stubFalse function from lodash returns a new function that always returns false. This is useful when testing functions that require a callback function, but the callback function itself does not need to perform any logic.

Here's an example of how to use stubFalse:

index.tsx
const _ = require('lodash');

function myFunction(callback) {
  const result = calculateResult(); // some logic goes here
  if (result === true) {
    callback(null, result);
  } else {
    callback(new Error('Result is not true'));
  }
}

// When testing, we can pass in a stubbed callback function that always returns false
const fakeCallback = _.stubFalse();

myFunction(fakeCallback); // This will always call the callback with an error
441 chars
16 lines

In this example, we're using stubFalse to create a fake callback function that always returns false. We then pass this function into myFunction when testing it.

Note that in a real-world scenario, you would likely want to use a more meaningful callback function when running your code for real. However, when unit testing, using stub functions like this can help simplify your tests and make them easier to reason about.