Type Alias FromJSONSchema<S, Defs, Depth, Mode>

FromJSONSchema: MergeRootDefs<S, Defs> extends infer MergedDefs extends
    Record<string, unknown>
    ? S extends { nullable: true }
        ? FromJSONSchema<Omit<S, "nullable">, MergedDefs, Depth, Mode> | null
        : S extends { $ref: infer R extends string }
            ? ResolveSchemaRef<R, MergedDefs, Depth, Mode>
            : S extends { $recursiveRef: string }
                ? unknown
                : S extends { $dynamicRef: infer R extends string }
                    ? ResolveSchemaRef<R, MergedDefs, Depth, Mode>
                    : S extends { allOf: infer A }
                        ? AllOfToType<A, MergedDefs, Depth, Mode>
                        : S extends { anyOf: infer A }
                            ? UnionOfMembers<A, MergedDefs, Depth, Mode>
                            : S extends {
                                oneOf: infer A;
                                discriminator: { propertyName: infer DP extends (...) };
                            }
                                ? DiscriminatedOneOfToUnion<
                                    A,
                                    DP,
                                    GetDiscriminatorMapping<S>,
                                    MergedDefs,
                                    Depth,
                                    Mode,
                                >
                                : S extends { oneOf: infer A }
                                    ? UnionOfMembers<A, MergedDefs, Depth, Mode>
                                    : S extends { if: ... }
                                        ? FromJSONSchema<(...), (...), (...), (...)>
                                        : (...) extends (...) ? (...) : (...)
    : unknown

Maps a JSON Schema structure to a TypeScript type. Works with as const literals -- provides full autocomplete for fields.

Supports all JSON Schema draft versions (04-2020-12) and OpenAPI 3.x:

Primitive types: string, number, integer, boolean, null
type as array: ["string", "null"] -> string | null (nullable)
enum -> union of literal types
const -> literal type
object with properties/required -> specific object type
object with properties + additionalProperties -> object & Record<string, V>
object with additionalProperties only -> Record<string, T>
array with items -> T[]
array with prefixItems -> tuple type
allOf -> intersection type
anyOf -> union type
oneOf -> union type (plain union, or tagged union when discriminator is set)
$ref -> resolved via $defs/definitions/$anchor context
$dynamicRef -> resolved via $dynamicAnchor in definitions
$recursiveRef -> unknown (recursive types not expressible in TS)
if/then/else -> base schema (conditionals not expressible in TS)
not -> unknown (negation not expressible in TS)
patternProperties -> merged into loose index signature

The Mode parameter controls how readOnly / writeOnly keywords influence inferred object properties — see FromJSONSchemaMode.

Type Parameters

S
Defs extends Record<string, unknown> = Record<string, never>
Depth extends readonly unknown[] = []
Mode extends FromJSONSchemaMode = "both"

Type Alias FromJSONSchema<S, Defs, Depth, Mode>

Type Parameters

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