Internal State Validation with Node.js Assert

Snippet

Internal State Validation with Node.js Assert

The 'node:assert' module provides functions for verifying internal invariants. While not a replacement for user input validation, it is essential for defensive programming to ensure that logic assumptions remain true during execution.

snippet.js

javascript

import assert from 'node:assert';
 
function processOrder(price, quantity) {
  assert(typeof price === 'number', 'Price must be a number');
  assert(quantity > 0, 'Quantity must be at least 1');
  
  const total = price * quantity;
  assert.strictEqual(total, price * quantity, 'Calculation integrity failure');
  
  return total;
}
 
try {
  processOrder(19.99, -1);
} catch (err) {
  console.log('Validation failed:', err.message);
}

nodejs

Breakdown

import assert from 'node:assert';

Imports the built-in assertion module for Node.js.

assert(condition, message);

Throws an AssertionError if the condition evaluates to false.

assert.strictEqual(a, b, msg);

Ensures that two values are identical using strict equality (===).

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Internal State Validation with Node.js Assert

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