@sinclair/typebox
Version:
Json Schema Type Builder with Static Type Resolution for TypeScript
215 lines (214 loc) • 9.59 kB
JavaScript
import { IsObject, IsArray, IsString, IsNumber, IsNull } from '../guard/index.mjs';
import { TypeBoxError } from '../../type/error/index.mjs';
import { Kind } from '../../type/symbols/index.mjs';
import { Create } from '../create/index.mjs';
import { Check } from '../check/index.mjs';
import { Clone } from '../clone/index.mjs';
import { Deref, Pushref } from '../deref/index.mjs';
// ------------------------------------------------------------------
// Errors
// ------------------------------------------------------------------
export class ValueCastError extends TypeBoxError {
constructor(schema, message) {
super(message);
this.schema = schema;
}
}
// ------------------------------------------------------------------
// The following will score a schema against a value. For objects,
// the score is the tally of points awarded for each property of
// the value. Property points are (1.0 / propertyCount) to prevent
// large property counts biasing results. Properties that match
// literal values are maximally awarded as literals are typically
// used as union discriminator fields.
// ------------------------------------------------------------------
function ScoreUnion(schema, references, value) {
if (schema[Kind] === 'Object' && typeof value === 'object' && !IsNull(value)) {
const object = schema;
const keys = Object.getOwnPropertyNames(value);
const entries = Object.entries(object.properties);
const [point, max] = [1 / entries.length, entries.length];
return entries.reduce((acc, [key, schema]) => {
const literal = schema[Kind] === 'Literal' && schema.const === value[key] ? max : 0;
const checks = Check(schema, references, value[key]) ? point : 0;
const exists = keys.includes(key) ? point : 0;
return acc + (literal + checks + exists);
}, 0);
}
else {
return Check(schema, references, value) ? 1 : 0;
}
}
function SelectUnion(union, references, value) {
const schemas = union.anyOf.map((schema) => Deref(schema, references));
let [select, best] = [schemas[0], 0];
for (const schema of schemas) {
const score = ScoreUnion(schema, references, value);
if (score > best) {
select = schema;
best = score;
}
}
return select;
}
function CastUnion(union, references, value) {
if ('default' in union) {
return typeof value === 'function' ? union.default : Clone(union.default);
}
else {
const schema = SelectUnion(union, references, value);
return Cast(schema, references, value);
}
}
// ------------------------------------------------------------------
// Default
// ------------------------------------------------------------------
function DefaultClone(schema, references, value) {
return Check(schema, references, value) ? Clone(value) : Create(schema, references);
}
function Default(schema, references, value) {
return Check(schema, references, value) ? value : Create(schema, references);
}
// ------------------------------------------------------------------
// Cast
// ------------------------------------------------------------------
function FromArray(schema, references, value) {
if (Check(schema, references, value))
return Clone(value);
const created = IsArray(value) ? Clone(value) : Create(schema, references);
const minimum = IsNumber(schema.minItems) && created.length < schema.minItems ? [...created, ...Array.from({ length: schema.minItems - created.length }, () => null)] : created;
const maximum = IsNumber(schema.maxItems) && minimum.length > schema.maxItems ? minimum.slice(0, schema.maxItems) : minimum;
const casted = maximum.map((value) => Visit(schema.items, references, value));
if (schema.uniqueItems !== true)
return casted;
const unique = [...new Set(casted)];
if (!Check(schema, references, unique))
throw new ValueCastError(schema, 'Array cast produced invalid data due to uniqueItems constraint');
return unique;
}
function FromConstructor(schema, references, value) {
if (Check(schema, references, value))
return Create(schema, references);
const required = new Set(schema.returns.required || []);
const result = function () { };
for (const [key, property] of Object.entries(schema.returns.properties)) {
if (!required.has(key) && value.prototype[key] === undefined)
continue;
result.prototype[key] = Visit(property, references, value.prototype[key]);
}
return result;
}
function FromImport(schema, references, value) {
const definitions = globalThis.Object.values(schema.$defs);
const target = schema.$defs[schema.$ref];
return Visit(target, [...references, ...definitions], value);
}
function FromIntersect(schema, references, value) {
const created = Create(schema, references);
const mapped = IsObject(created) && IsObject(value) ? { ...created, ...value } : value;
return Check(schema, references, mapped) ? mapped : Create(schema, references);
}
function FromNever(schema, references, value) {
throw new ValueCastError(schema, 'Never types cannot be cast');
}
function FromObject(schema, references, value) {
if (Check(schema, references, value))
return value;
if (value === null || typeof value !== 'object')
return Create(schema, references);
const required = new Set(schema.required || []);
const result = {};
for (const [key, property] of Object.entries(schema.properties)) {
if (!required.has(key) && value[key] === undefined)
continue;
result[key] = Visit(property, references, value[key]);
}
// additional schema properties
if (typeof schema.additionalProperties === 'object') {
const propertyNames = Object.getOwnPropertyNames(schema.properties);
for (const propertyName of Object.getOwnPropertyNames(value)) {
if (propertyNames.includes(propertyName))
continue;
result[propertyName] = Visit(schema.additionalProperties, references, value[propertyName]);
}
}
return result;
}
function FromRecord(schema, references, value) {
if (Check(schema, references, value))
return Clone(value);
if (value === null || typeof value !== 'object' || Array.isArray(value) || value instanceof Date)
return Create(schema, references);
const subschemaPropertyName = Object.getOwnPropertyNames(schema.patternProperties)[0];
const subschema = schema.patternProperties[subschemaPropertyName];
const result = {};
for (const [propKey, propValue] of Object.entries(value)) {
result[propKey] = Visit(subschema, references, propValue);
}
return result;
}
function FromRef(schema, references, value) {
return Visit(Deref(schema, references), references, value);
}
function FromThis(schema, references, value) {
return Visit(Deref(schema, references), references, value);
}
function FromTuple(schema, references, value) {
if (Check(schema, references, value))
return Clone(value);
if (!IsArray(value))
return Create(schema, references);
if (schema.items === undefined)
return [];
return schema.items.map((schema, index) => Visit(schema, references, value[index]));
}
function FromUnion(schema, references, value) {
return Check(schema, references, value) ? Clone(value) : CastUnion(schema, references, value);
}
function Visit(schema, references, value) {
const references_ = IsString(schema.$id) ? Pushref(schema, references) : references;
const schema_ = schema;
switch (schema[Kind]) {
// --------------------------------------------------------------
// Structural
// --------------------------------------------------------------
case 'Array':
return FromArray(schema_, references_, value);
case 'Constructor':
return FromConstructor(schema_, references_, value);
case 'Import':
return FromImport(schema_, references_, value);
case 'Intersect':
return FromIntersect(schema_, references_, value);
case 'Never':
return FromNever(schema_, references_, value);
case 'Object':
return FromObject(schema_, references_, value);
case 'Record':
return FromRecord(schema_, references_, value);
case 'Ref':
return FromRef(schema_, references_, value);
case 'This':
return FromThis(schema_, references_, value);
case 'Tuple':
return FromTuple(schema_, references_, value);
case 'Union':
return FromUnion(schema_, references_, value);
// --------------------------------------------------------------
// DefaultClone
// --------------------------------------------------------------
case 'Date':
case 'Symbol':
case 'Uint8Array':
return DefaultClone(schema, references, value);
// --------------------------------------------------------------
// Default
// --------------------------------------------------------------
default:
return Default(schema_, references_, value);
}
}
/** Casts a value into a given type. The return value will retain as much information of the original value as possible. */
export function Cast(...args) {
return args.length === 3 ? Visit(args[0], args[1], args[2]) : Visit(args[0], [], args[1]);
}