399 lines
11 KiB
Plaintext
399 lines
11 KiB
Plaintext
/**
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* @typedef {import('unist').Node} UnistNode
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* @typedef {import('unist').Parent} UnistParent
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*/
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/**
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* @typedef {Exclude<import('unist-util-is').Test, undefined> | undefined} Test
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* Test from `unist-util-is`.
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*
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* Note: we have remove and add `undefined`, because otherwise when generating
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* automatic `.d.ts` files, TS tries to flatten paths from a local perspective,
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* which doesn’t work when publishing on npm.
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*/
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/**
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* @typedef {(
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* Fn extends (value: any) => value is infer Thing
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* ? Thing
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* : Fallback
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* )} Predicate
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* Get the value of a type guard `Fn`.
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* @template Fn
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* Value; typically function that is a type guard (such as `(x): x is Y`).
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* @template Fallback
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* Value to yield if `Fn` is not a type guard.
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*/
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/**
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* @typedef {(
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* Check extends null | undefined // No test.
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* ? Value
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* : Value extends {type: Check} // String (type) test.
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* ? Value
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* : Value extends Check // Partial test.
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* ? Value
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* : Check extends Function // Function test.
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* ? Predicate<Check, Value> extends Value
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* ? Predicate<Check, Value>
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* : never
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* : never // Some other test?
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* )} MatchesOne
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* Check whether a node matches a primitive check in the type system.
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* @template Value
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* Value; typically unist `Node`.
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* @template Check
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* Value; typically `unist-util-is`-compatible test, but not arrays.
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*/
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/**
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* @typedef {(
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* Check extends Array<any>
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* ? MatchesOne<Value, Check[keyof Check]>
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* : MatchesOne<Value, Check>
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* )} Matches
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* Check whether a node matches a check in the type system.
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* @template Value
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* Value; typically unist `Node`.
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* @template Check
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* Value; typically `unist-util-is`-compatible test.
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*/
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/**
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* @typedef {0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10} Uint
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* Number; capped reasonably.
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*/
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/**
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* @typedef {I extends 0 ? 1 : I extends 1 ? 2 : I extends 2 ? 3 : I extends 3 ? 4 : I extends 4 ? 5 : I extends 5 ? 6 : I extends 6 ? 7 : I extends 7 ? 8 : I extends 8 ? 9 : 10} Increment
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* Increment a number in the type system.
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* @template {Uint} [I=0]
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* Index.
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*/
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/**
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* @typedef {(
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* Node extends UnistParent
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* ? Node extends {children: Array<infer Children>}
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* ? Child extends Children ? Node : never
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* : never
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* : never
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* )} InternalParent
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* Collect nodes that can be parents of `Child`.
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* @template {UnistNode} Node
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* All node types in a tree.
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* @template {UnistNode} Child
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* Node to search for.
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*/
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/**
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* @typedef {InternalParent<InclusiveDescendant<Tree>, Child>} Parent
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* Collect nodes in `Tree` that can be parents of `Child`.
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* @template {UnistNode} Tree
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* All node types in a tree.
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* @template {UnistNode} Child
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* Node to search for.
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*/
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/**
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* @typedef {(
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* Depth extends Max
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* ? never
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* :
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* | InternalParent<Node, Child>
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* | InternalAncestor<Node, InternalParent<Node, Child>, Max, Increment<Depth>>
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* )} InternalAncestor
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* Collect nodes in `Tree` that can be ancestors of `Child`.
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* @template {UnistNode} Node
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* All node types in a tree.
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* @template {UnistNode} Child
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* Node to search for.
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* @template {Uint} [Max=10]
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* Max; searches up to this depth.
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* @template {Uint} [Depth=0]
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* Current depth.
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*/
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/**
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* @typedef {InternalAncestor<InclusiveDescendant<Tree>, Child>} Ancestor
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* Collect nodes in `Tree` that can be ancestors of `Child`.
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* @template {UnistNode} Tree
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* All node types in a tree.
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* @template {UnistNode} Child
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* Node to search for.
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*/
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/**
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* @typedef {(
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* Tree extends UnistParent
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* ? Depth extends Max
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* ? Tree
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* : Tree | InclusiveDescendant<Tree['children'][number], Max, Increment<Depth>>
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* : Tree
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* )} InclusiveDescendant
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* Collect all (inclusive) descendants of `Tree`.
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*
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* > 👉 **Note**: for performance reasons, this seems to be the fastest way to
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* > recurse without actually running into an infinite loop, which the
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* > previous version did.
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* >
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* > Practically, a max of `2` is typically enough assuming a `Root` is
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* > passed, but it doesn’t improve performance.
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* > It gets higher with `List > ListItem > Table > TableRow > TableCell`.
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* > Using up to `10` doesn’t hurt or help either.
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* @template {UnistNode} Tree
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* Tree type.
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* @template {Uint} [Max=10]
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* Max; searches up to this depth.
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* @template {Uint} [Depth=0]
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* Current depth.
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*/
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/**
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* @typedef {'skip' | boolean} Action
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* Union of the action types.
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*
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* @typedef {number} Index
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* Move to the sibling at `index` next (after node itself is completely
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* traversed).
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*
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* Useful if mutating the tree, such as removing the node the visitor is
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* currently on, or any of its previous siblings.
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* Results less than 0 or greater than or equal to `children.length` stop
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* traversing the parent.
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*
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* @typedef {[(Action | null | undefined | void)?, (Index | null | undefined)?]} ActionTuple
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* List with one or two values, the first an action, the second an index.
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*
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* @typedef {Action | ActionTuple | Index | null | undefined | void} VisitorResult
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* Any value that can be returned from a visitor.
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*/
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/**
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* @callback Visitor
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* Handle a node (matching `test`, if given).
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*
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* Visitors are free to transform `node`.
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* They can also transform the parent of node (the last of `ancestors`).
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*
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* Replacing `node` itself, if `SKIP` is not returned, still causes its
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* descendants to be walked (which is a bug).
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*
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* When adding or removing previous siblings of `node` (or next siblings, in
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* case of reverse), the `Visitor` should return a new `Index` to specify the
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* sibling to traverse after `node` is traversed.
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* Adding or removing next siblings of `node` (or previous siblings, in case
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* of reverse) is handled as expected without needing to return a new `Index`.
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*
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* Removing the children property of an ancestor still results in them being
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* traversed.
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* @param {Visited} node
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* Found node.
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* @param {Array<VisitedParents>} ancestors
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* Ancestors of `node`.
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* @returns {VisitorResult}
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* What to do next.
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*
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* An `Index` is treated as a tuple of `[CONTINUE, Index]`.
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* An `Action` is treated as a tuple of `[Action]`.
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*
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* Passing a tuple back only makes sense if the `Action` is `SKIP`.
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* When the `Action` is `EXIT`, that action can be returned.
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* When the `Action` is `CONTINUE`, `Index` can be returned.
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* @template {UnistNode} [Visited=UnistNode]
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* Visited node type.
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* @template {UnistParent} [VisitedParents=UnistParent]
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* Ancestor type.
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*/
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/**
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* @typedef {Visitor<Matches<InclusiveDescendant<Tree>, Check>, Ancestor<Tree, Matches<InclusiveDescendant<Tree>, Check>>>} BuildVisitor
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* Build a typed `Visitor` function from a tree and a test.
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*
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* It will infer which values are passed as `node` and which as `parents`.
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* @template {UnistNode} [Tree=UnistNode]
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* Tree type.
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* @template {Test} [Check=Test]
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* Test type.
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*/
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import {convert} from 'unist-util-is'
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import {color} from 'unist-util-visit-parents/do-not-use-color'
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/** @type {Readonly<ActionTuple>} */
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const empty = []
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/**
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* Continue traversing as normal.
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*/
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export const CONTINUE = true
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/**
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* Stop traversing immediately.
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*/
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export const EXIT = false
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/**
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* Do not traverse this node’s children.
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*/
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export const SKIP = 'skip'
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/**
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* Visit nodes, with ancestral information.
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*
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* This algorithm performs *depth-first* *tree traversal* in *preorder*
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* (**NLR**) or if `reverse` is given, in *reverse preorder* (**NRL**).
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*
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* You can choose for which nodes `visitor` is called by passing a `test`.
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* For complex tests, you should test yourself in `visitor`, as it will be
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* faster and will have improved type information.
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*
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* Walking the tree is an intensive task.
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* Make use of the return values of the visitor when possible.
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* Instead of walking a tree multiple times, walk it once, use `unist-util-is`
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* to check if a node matches, and then perform different operations.
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*
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* You can change the tree.
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* See `Visitor` for more info.
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*
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* @overload
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* @param {Tree} tree
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* @param {Check} check
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* @param {BuildVisitor<Tree, Check>} visitor
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* @param {boolean | null | undefined} [reverse]
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* @returns {undefined}
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*
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* @overload
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* @param {Tree} tree
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* @param {BuildVisitor<Tree>} visitor
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* @param {boolean | null | undefined} [reverse]
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* @returns {undefined}
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*
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* @param {UnistNode} tree
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* Tree to traverse.
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* @param {Visitor | Test} test
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* `unist-util-is`-compatible test
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* @param {Visitor | boolean | null | undefined} [visitor]
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* Handle each node.
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* @param {boolean | null | undefined} [reverse]
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* Traverse in reverse preorder (NRL) instead of the default preorder (NLR).
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* @returns {undefined}
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* Nothing.
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*
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* @template {UnistNode} Tree
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* Node type.
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* @template {Test} Check
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* `unist-util-is`-compatible test.
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*/
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export function visitParents(tree, test, visitor, reverse) {
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/** @type {Test} */
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let check
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if (typeof test === 'function' && typeof visitor !== 'function') {
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reverse = visitor
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// @ts-expect-error no visitor given, so `visitor` is test.
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visitor = test
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} else {
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// @ts-expect-error visitor given, so `test` isn’t a visitor.
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check = test
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}
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const is = convert(check)
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const step = reverse ? -1 : 1
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factory(tree, undefined, [])()
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/**
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* @param {UnistNode} node
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* @param {number | undefined} index
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* @param {Array<UnistParent>} parents
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*/
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function factory(node, index, parents) {
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const value = /** @type {Record<string, unknown>} */ (
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node && typeof node === 'object' ? node : {}
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)
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if (typeof value.type === 'string') {
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const name =
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// `hast`
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typeof value.tagName === 'string'
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? value.tagName
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: // `xast`
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typeof value.name === 'string'
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? value.name
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: undefined
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Object.defineProperty(visit, 'name', {
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value:
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'node (' + color(node.type + (name ? '<' + name + '>' : '')) + ')'
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})
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}
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return visit
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function visit() {
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/** @type {Readonly<ActionTuple>} */
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let result = empty
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/** @type {Readonly<ActionTuple>} */
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let subresult
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/** @type {number} */
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let offset
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/** @type {Array<UnistParent>} */
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let grandparents
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if (!test || is(node, index, parents[parents.length - 1] || undefined)) {
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// @ts-expect-error: `visitor` is now a visitor.
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result = toResult(visitor(node, parents))
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if (result[0] === EXIT) {
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return result
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}
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}
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if ('children' in node && node.children) {
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const nodeAsParent = /** @type {UnistParent} */ (node)
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if (nodeAsParent.children && result[0] !== SKIP) {
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offset = (reverse ? nodeAsParent.children.length : -1) + step
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grandparents = parents.concat(nodeAsParent)
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while (offset > -1 && offset < nodeAsParent.children.length) {
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const child = nodeAsParent.children[offset]
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subresult = factory(child, offset, grandparents)()
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if (subresult[0] === EXIT) {
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return subresult
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}
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offset =
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typeof subresult[1] === 'number' ? subresult[1] : offset + step
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}
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}
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}
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return result
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}
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}
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}
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/**
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* Turn a return value into a clean result.
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*
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* @param {VisitorResult} value
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* Valid return values from visitors.
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* @returns {Readonly<ActionTuple>}
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* Clean result.
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*/
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function toResult(value) {
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if (Array.isArray(value)) {
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return value
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}
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if (typeof value === 'number') {
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return [CONTINUE, value]
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}
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return value === null || value === undefined ? empty : [value]
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}
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