| 1 | /** |
| 2 | * A value that survives `JSON.stringify` unchanged and is accepted on the wire: |
| 3 | * `null`, booleans, strings, finite numbers, dense arrays, and plain objects |
| 4 | * whose own keys are enumerable string data properties. Holes, extra array |
| 5 | * properties, accessors and symbol keys would serialize to something other |
| 6 | * than what was checked (a hole becomes `null`, a getter can answer twice), so |
| 7 | * they are refused rather than passed to Rust as a different value. |
| 8 | */ |
| 9 | import type { Json } from './protocol.ts' |
| 10 | |
| 11 | export function isJson(value: unknown, depth = 0): value is Json { |
| 12 | if (depth > 64) return false |
| 13 | if (value === null) return true |
| 14 | switch (typeof value) { |
| 15 | case 'boolean': |
| 16 | case 'string': |
| 17 | return true |
| 18 | case 'number': |
| 19 | return Number.isFinite(value) |
| 20 | case 'object': { |
| 21 | const array = Array.isArray(value) |
| 22 | if (!array && Object.getPrototypeOf(value) !== Object.prototype && Object.getPrototypeOf(value) !== null) return false |
| 23 | const keys = Reflect.ownKeys(value as object) |
| 24 | if (array && keys.length !== (value as unknown[]).length + 1) return false |
| 25 | for (const key of keys) { |
| 26 | if (array && key === 'length') continue |
| 27 | if (typeof key !== 'string') return false |
| 28 | if (array && (!/^(0|[1-9]\d*)$/u.test(key) || Number(key) >= (value as unknown[]).length)) return false |
| 29 | const descriptor = Object.getOwnPropertyDescriptor(value, key)! |
| 30 | if (!descriptor.enumerable || !('value' in descriptor) || !isJson(descriptor.value, depth + 1)) return false |
| 31 | } |
| 32 | return true |
| 33 | } |
| 34 | default: |
| 35 | return false |
| 36 | } |
| 37 | } |
| 38 |