Node.js assert tracker.calls() Function
Last Updated :
14 May, 2022
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The tracker.calls() method is used to keep track of the number of times a function is executed. It returns a wrapper function that should be invoked at exact times. When tracker.verify() is executed, if the method has not been called precisely exact times, tracker.verify() will throw an exception.
Syntax:
tracker.calls([fn][, exact])
Parameters:
- fn: The function to be monitored. A no-op function is the default value.
- exact (number): The number of times. Its default value is 1.
Return Value: A wrapper function that wraps fn.
Example 1:
import assert from 'node:assert';
const tracker = new assert.CallTracker();
function func() { console.log("Hello World") };
const callsfunc = tracker.calls(func, 2);
callsfunc();
callsfunc();
process.on('exit', () => {
tracker.verify()
});
Output:
Hello World Hello World
Example 2:
import assert from 'node:assert';
const tracker = new assert.CallTracker();
function func() { console.log("Hello World") };
const callsfunc = tracker.calls(func, 2);
callsfunc();
process.on('exit', () => {
tracker.verify()
});
Output:
Reference: https://nodejs.org/api/assert.html#trackercallsfn-exact
