Node.js assert tracker.verify() Function

The tracker.verify() method is used to verify the how many times function was actually called compared to expected number of calls. This function will throw an error if the actual and expected number of calls are not the same.

Syntax:

tracker.verify()

Parameters: This function does not accepts any parameter.

Return Value: It returns void.

Below examplesillustrate the assert tracker.verify() function in nodejs.

Example 1:

Javascript

const assert = require('assert');

// Creates call tracker.
const tracker = new assert.CallTracker();

function func() {}

// Returns a function that wraps func() that must be called exact times
// before tracker.verify().
const callsfunc = tracker.calls(func, 2);

// called func through callsfunc only 1 time
callsfunc();

console.log(tracker.verify());

Output:

Example 2:

Javascript

const assert = require('assert');

// Creates call tracker.
const tracker = new assert.CallTracker();

function func() {}

// Returns a function that wraps func() that must be called exact times
// before tracker.verify().
const callsfunc = tracker.calls(func, 2);

// called func through callsfunc only 2 times
callsfunc();
callsfunc();

console.log(tracker.verify());

Output:

Reference:https://nodejs.org/api/assert.html#assert_tracker_verify