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Fix: Handle null values correctly to prevent TypeError#2

opennull-pointer wants to merge

null-pointer

Fixes #3.

typeof null is object, which caused the validator to proceed into the object check block. Accessing field in data on null throws a TypeError.

This fix explicitly treats null as type null, which causes the type check to fail (as expected) instead of crashing.

Files changed (1)

src/index.tsmodify

1	+	export type Schema = {
2	+	type: 'string' \| 'number' \| 'boolean' \| 'object' \| 'array';
3	+	required?: string[];
4	+	properties?: Record<string, Schema>;
5	+	};
6	+
7	+	export class ValidationError extends Error {
8	+	constructor(public path: string, public message: string) {
9	+	super(`Validation failed at ${path}: ${message}`);
10	+	this.name = 'ValidationError';
11	+	}
12	+	}
13	+
14	+	export function police(data: any, schema: Schema, path: string = 'root'): void {
15	+	let dataType = typeof data;
16	+	if (data === null) dataType = 'null';
17	+	if (Array.isArray(data)) dataType = 'array';
18	+
19	+	if (dataType !== schema.type) {
20	+	throw new ValidationError(path, `Expected ${schema.type}, got ${dataType}`);
21	+	}
22	+
23	+	if (schema.type === 'object' && schema.properties) {
24	+	// Check required fields
25	+	if (schema.required) {
26	+	for (const field of schema.required) {
27	+	if (!(field in data)) {
28	+	throw new ValidationError(`${path}.${field}`, 'Missing required field');
29	+	}
30	+	}
31	+	}
32	+
33	+	// Validate properties
34	+	for (const [key, propSchema] of Object.entries(schema.properties)) {
35	+	if (key in data) {
36	+	police(data[key], propSchema, `${path}.${key}`);
37	+	}
38	+	}
39	+	}
40	+	}