import assert from 'node:assert/strict';
import { describe, it } from 'node:test';
import { stableStringify } from '../dist/lib/json.js';
describe('stableStringify', () => {
it('should stringify normal objects with sorted keys', () => {
const obj = { b: 2, a: 1, c: 3 };
const result = stableStringify(obj);
assert.equal(result, '{"a":1,"b":2,"c":3}');
});
it('should detect circular references in objects', () => {
const obj: Record<string, unknown> = { a: 1 };
obj.self = obj; // Circular ref
assert.throws(
() => {
stableStringify(obj);
},
/Circular reference detected/,
'Expected circular reference error'
);
});
it('should reject deeply nested objects (depth > 20)', () => {
let deep: Record<string, unknown> = { value: 1 };
for (let i = 0; i < 25; i++) {
deep = { nested: deep };
}
assert.throws(
() => {
stableStringify(deep);
},
/Max depth.*exceeded/,
'Expected max depth error'
);
});
it('should accept objects at max depth (20)', () => {
let deep: Record<string, unknown> = { value: 1 };
for (let i = 0; i < 19; i++) {
deep = { nested: deep };
}
const result = stableStringify(deep);
assert.ok(result.includes('"value":1'), 'Should stringify deep object');
});
it('should detect circular refs in arrays', () => {
const arr: unknown[] = [1, 2];
arr.push(arr); // Circular
assert.throws(
() => {
stableStringify(arr);
},
/Circular reference detected/,
'Expected circular reference error in array'
);
});
it('should handle primitives', () => {
assert.equal(stableStringify(42), '42');
assert.equal(stableStringify('hello'), '"hello"');
assert.equal(stableStringify(true), 'true');
assert.equal(stableStringify(null), 'null');
});
it('matches JSON stringify omission/null behavior for unsupported values', () => {
const fn = (): void => {};
const sym = Symbol('x');
const value = {
keep: 1,
dropUndefined: undefined,
dropFn: fn,
dropSymbol: sym,
arr: [undefined, fn, sym, 1],
};
const result = stableStringify(value);
assert.equal(result, '{"arr":[null,null,null,1],"keep":1}');
});
it('treats Date objects as plain objects (no toJSON conversion)', () => {
const result = stableStringify({
createdAt: new Date('2024-01-01T00:00:00.000Z'),
});
assert.equal(result, '{"createdAt":{}}');
});
it('should sort nested object keys', () => {
const obj = {
z: { b: 2, a: 1 },
a: { y: 3, x: 2 },
};
const result = stableStringify(obj);
// Keys should be sorted at every level
assert.ok(result.includes('"a":{"x":2,"y":3}'));
assert.ok(result.includes('"z":{"a":1,"b":2}'));
});
});
