@sinclair/typebox
Version:
Json Schema Type Builder with Static Type Resolution for TypeScript
26 lines (25 loc) • 1.31 kB
JavaScript
import { CreateType } from '../create/type.mjs';
import { Union } from '../union/index.mjs';
import { Never } from '../never/index.mjs';
import { ExtendsCheck, ExtendsResult } from '../extends/index.mjs';
import { ExtractFromMappedResult } from './extract-from-mapped-result.mjs';
import { ExtractFromTemplateLiteral } from './extract-from-template-literal.mjs';
// ------------------------------------------------------------------
// TypeGuard
// ------------------------------------------------------------------
import { IsMappedResult, IsTemplateLiteral, IsUnion } from '../guard/kind.mjs';
function ExtractRest(L, R) {
const extracted = L.filter((inner) => ExtendsCheck(inner, R) !== ExtendsResult.False);
return extracted.length === 1 ? extracted[0] : Union(extracted);
}
/** `[Json]` Constructs a type by extracting from type all union members that are assignable to union */
export function Extract(L, R, options) {
// overloads
if (IsTemplateLiteral(L))
return CreateType(ExtractFromTemplateLiteral(L, R), options);
if (IsMappedResult(L))
return CreateType(ExtractFromMappedResult(L, R), options);
// prettier-ignore
return CreateType(IsUnion(L) ? ExtractRest(L.anyOf, R) :
ExtendsCheck(L, R) !== ExtendsResult.False ? L : Never(), options);
}