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