Function letrec

letrec<T>(
    builder: T extends Record<string, unknown>
        ? LetrecTypedBuilder<T<T>>
        : never,
): LetrecValue<T>

For mutually recursive types

Type Parameters

Parameters

builder: T extends Record<string, unknown> ? LetrecTypedBuilder<T<T>> : never
Arbitraries builder based on themselves (through tie)

Returns LetrecValue<T>

Example

type Leaf = number;
type Node = [Tree, Tree];
type Tree = Node | Leaf;
const { tree } = fc.letrec<{ tree: Tree, node: Node, leaf: Leaf }>(tie => ({
  tree: fc.oneof({depthSize: 'small'}, tie('leaf'), tie('node')),
  node: fc.tuple(tie('tree'), tie('tree')),
  leaf: fc.nat()
}));
// tree is 50% of node, 50% of leaf
// the ratio goes in favor of leaves as we go deeper in the tree (thanks to depthSize)

Remarks

Since 1.16.0

letrec<T>(builder: LetrecLooselyTypedBuilder<T>): LetrecValue<T>

For mutually recursive types

Type Parameters

Parameters

builder: LetrecLooselyTypedBuilder<T>
Arbitraries builder based on themselves (through tie)

Returns LetrecValue<T>

Example

const { tree } = fc.letrec(tie => ({
  tree: fc.oneof({depthSize: 'small'}, tie('leaf'), tie('node')),
  node: fc.tuple(tie('tree'), tie('tree')),
  leaf: fc.nat()
}));
// tree is 50% of node, 50% of leaf
// the ratio goes in favor of leaves as we go deeper in the tree (thanks to depthSize)

Remarks

Since 1.16.0

Function letrec

Type Parameters

Parameters

Returns LetrecValue<T>

Example

Remarks

Type Parameters

Parameters

Returns LetrecValue<T>

Example

Remarks

Settings