export type JSONPrimitive = string | number | boolean | null | undefined;export type JSONValue = JSONPrimitive | JSONObject | JSONArray;export type JSONObject = {[key: string]: JSONValue};export type JSONArray = JSONValue[];
export type FieldTypeIn = | 's' | 'n' | 'b' | 'd' | 'a' | ((obj: JSONValue) => any);const FieldTypeNames = { s: 'string', n: 'number', b: 'boolean', d: 'date', a: 'blob',};
type ResolveFieldTypeIn< T extends FieldTypeIn | [FieldTypeIn], U = T extends [infer R] ? R : T, V = U extends (obj: JSONValue) => null | infer R ? R : U extends 's' ? string : U extends 'n' ? number : U extends 'b' ? boolean : U extends 'd' ? Date : U extends 'a' ? Uint8Array : never,> = T extends [any] ? V[] : V;
export function readObj< R extends {[key: string]: (FieldTypeIn | [FieldTypeIn])}, O extends {[key: string]: (FieldTypeIn | [FieldTypeIn])},>( opts: { required: R, optional: O, remap?: {[key: string]: keyof R | keyof O}, }, data: JSONValue,): {[key in keyof R | keyof O] : key extends keyof R ? ResolveFieldTypeIn<R[key]> : key extends keyof O ? (ResolveFieldTypeIn<O[key]> | null) : never} { if (data === null || typeof data !== "object" || Array.isArray(data)) { throw new Error(`Object wasn't an object, was ${typeof data}, wanted keys ${JSON.stringify(Object.keys(opts.required).concat(Object.keys(opts.optional)))}`); }
const remap = opts.remap ?? {}; const missing = new Set<string>(Object.keys(opts.required)); const problems = new Array<string>(); const obj = Object.create(null);
for (const [key, raw] of Object.entries(data)) { const targetName = key in remap ? remap[key].toString() : key; const isRequired = targetName in opts.required; if (!isRequired && !(targetName in opts.optional)) continue;
if (raw == null) { obj[targetName] = null; } else { const typeSig = isRequired ? opts.required[targetName] : opts.optional[targetName]; const value = readField(typeSig, raw); if (value == null) { problems.push(`Key ${key} of type ${typeof raw} failed to parse as ${typeof typeSig === 'string' ? FieldTypeNames[typeSig] : typeof typeSig}`); } else { missing.delete(targetName); } obj[targetName] = value; } } if (problems.length > 0) throw new Error(`BUG: JSON object `+ `failed to read some keys: ${problems.join(' ; ') } - had keys ${JSON.stringify(Object.keys(data))}`); if (missing.size > 0) throwMissingKeys(missing, Object.keys(data));
return obj;}
function readField(typeSig: FieldTypeIn | [FieldTypeIn], raw: JSONValue): unknown { if (raw == null) return null; switch (typeSig) { case 's': return typeof raw === 'string' ? raw : null; case 'n': return typeof raw === 'number' ? raw : null; case 'b': return typeof raw === 'boolean' ? raw : null case 'd': return readDate(raw); case 'a': if (typeof raw === 'string') { return decodeBase64(raw); } break; default: if (typeof typeSig === 'function') { return typeSig(raw); } else if (Array.isArray(typeSig)) { if (Array.isArray(raw)) { return raw.map(readField.bind(null, typeSig[0])); } } } return null;}
function throwMissingKeys(missingKeys: Iterable<string>, hadKeys: Iterable<string>): never { throw new Error(`BUG: JSON object `+ `missing required keys ${JSON.stringify(Array.from(missingKeys)) } - had keys ${JSON.stringify(Array.from(hadKeys))}`);}
export function serializeDate_unixTimestamp(input: Date | number | null | undefined): JSONValue { if (input == null) return input; const date = typeof input === 'number' ? new Date(input*1000) : input; return Math.floor(date.valueOf() / 1000);}export function serializeDate_iso8601(input: Date | number | null | undefined): JSONValue { if (input == null) return input; const date = typeof input === 'number' ? new Date(input*1000) : input; return date.toISOString().replace(/\.000Z$/, 'Z');}export function serializeDate_rfc822(input: Date | number | null | undefined): JSONValue { if (input == null) return input; const date = typeof input === 'number' ? new Date(input*1000) : input; return date.toUTCString();}
export function readDate(raw: JSONValue): Date | null { if (typeof raw === 'string') { const date = new Date(raw); if (!isNaN(date.valueOf())) return date; } else if (typeof raw === 'number') { return new Date(raw * 1000); } return null;}
export function serializeMap<T,U extends JSONValue>(input: {[key: string]: T} | null | undefined, encoder: (x: T) => U): JSONValue { if (input == null) return input; const map: {[key: string]: U} = Object.create(null); for (const [key, val] of Object.entries(input)) { map[key] = encoder(val); } return map;}
export function serializeJsonValue(input: JSONValue): string | undefined { if (input === undefined) return input; return JSON.stringify(input);}export function readJsonValue(input: JSONValue): JSONValue { if (input == null || input == '') return undefined; if (typeof input !== 'string') throw new Error(`Server's JSON Value was ${typeof input} instead of string`); return JSON.parse(input);}export function readJsonValueBase64(input: JSONValue): JSONValue { if (input == null || input == '') return undefined; if (typeof input !== 'string') throw new Error(`Server's JSON Value was ${typeof input} instead of string`); return JSON.parse(atob(input));}
function decodeBase64(b64: string): Uint8Array { const binString = atob(b64); const size = binString.length; const bytes = new Uint8Array(size); for (let i = 0; i < size; i++) { bytes[i] = binString.charCodeAt(i); } return bytes;}
export function readMap<K extends string,V>(keyEncoder: (x: string) => K, valEncoder: (x: JSONValue) => V, input: JSONValue): Record<K,V> | null { if (input == null) return null; const map: Record<K,V> = Object.create(null); for (const [key, val] of Object.entries(input)) { map[keyEncoder(key)] = valEncoder(val); } return map;}
export function readList<V>(encoder: (x: JSONValue) => V, raw: JSONValue): V[] | null { if (Array.isArray(raw)) { return raw.map(encoder); } return null;}
export function readNum(raw: JSONValue): number { if (typeof raw === 'number') return raw; throw new Error(`readNum wanted a number, got a ${typeof raw}`);}