JavaScript Not Equal: Compare Mixed-Type IDs Explicitly

The task

Compare a numeric row ID with its textual spelling, plus two already normalized IDs. Do not silently assume that every external identifier should be converted to a number.

Runnable Node 22 example

const assert = require('node:assert/strict');

const stored = 24;
const incoming = '24';
assert.equal(stored !== incoming, true);
assert.equal(stored != incoming, false);
assert.equal('024' != stored, false);
assert.equal('24' !== '25', true);
assert.equal(0 != false, false);
assert.equal(0 !== false, true);
console.log(`strictDifferent=${stored !== incoming}; looseDifferent=${stored != incoming}`);

Expected output and explanation

The strict comparison treats the numeric value and string as different. The loose comparison treats them as equal in this case after conversion, so “not equal” becomes false. The leading-zero string also loses its textual distinction under that numeric-style comparison.

The Boolean example exposes another coercion boundary: zero and false are loosely equal but strictly different. These checked results explain the operators without claiming that either one validates identifiers. Normalize at a defined boundary only when the identifier specification permits it.

Pitfall to check

Converting all IDs with Number can destroy meaningful leading zeroes or exceed safe numeric precision. If identifiers are defined as text, keep them as text and validate the accepted form. A comparison operator cannot decide that domain rule for you.