Awesome
unist-util-visit
unist utility to walk the tree.
Contents
- What is this?
- When should I use this?
- Install
- Use
- API
- Types
- Compatibility
- Related
- Contribute
- License
What is this?
This is a very important utility for working with unist as it lets you walk the tree.
When should I use this?
You can use this utility when you want to walk the tree.
You can use unist-util-visit-parents
if you care about the entire stack
of parents.
Install
This package is ESM only. In Node.js (version 16+), install with npm:
npm install unist-util-visit
In Deno with esm.sh
:
import {CONTINUE, EXIT, SKIP, visit} from 'https://esm.sh/unist-util-visit@5'
In browsers with esm.sh
:
<script type="module">
import {CONTINUE, EXIT, SKIP, visit} from 'https://esm.sh/unist-util-visit@5?bundle'
</script>
Use
import {fromMarkdown} from 'mdast-util-from-markdown'
import {visit} from 'unist-util-visit'
const tree = fromMarkdown('Some *emphasis*, **strong**, and `code`.')
visit(tree, 'text', function (node, index, parent) {
console.log([node.value, parent ? parent.type : index])
})
Yields:
[ 'Some ', 'paragraph' ]
[ 'emphasis', 'emphasis' ]
[ ', ', 'paragraph' ]
[ 'strong', 'strong' ]
[ ', and ', 'paragraph' ]
[ '.', 'paragraph' ]
API
This package exports the identifiers CONTINUE
,
EXIT
, SKIP
, and visit
.
There is no default export.
visit(tree[, test], visitor[, reverse])
This function works exactly the same as unist-util-visit-parents
,
but Visitor
has a different signature.
CONTINUE
Continue traversing as normal (true
).
EXIT
Stop traversing immediately (false
).
SKIP
Do not traverse this node’s children ('skip'
).
Action
Union of the action types (TypeScript type).
See Action
in unist-util-visit-parents
.
ActionTuple
List with an action and an index (TypeScript type).
See ActionTuple
in unist-util-visit-parents
.
BuildVisitor
Build a typed Visitor
function from a tree and a test (TypeScript type).
See BuildVisitor
in unist-util-visit-parents
.
Index
Move to the sibling at index
next (TypeScript type).
See Index
in unist-util-visit-parents
.
Test
unist-util-is
compatible test (TypeScript type).
Visitor
Handle a node (matching test
, if given) (TypeScript type).
Visitors are free to transform node
.
They can also transform parent
.
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 parent
still results in them being
traversed.
Parameters
node
(Node
) — found nodeindex
(number
orundefined
) — index ofnode
inparent
parent
(Node
orundefined
) — parent ofnode
Returns
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.
VisitorResult
Any value that can be returned from a visitor (TypeScript type).
See VisitorResult
in unist-util-visit-parents
.
Types
This package is fully typed with TypeScript.
It exports the additional types Action
,
ActionTuple
, BuildVisitor
,
Index
, Test
, Visitor
, and
VisitorResult
.
Compatibility
Projects maintained by the unified collective are compatible with maintained versions of Node.js.
When we cut a new major release, we drop support for unmaintained versions of
Node.
This means we try to keep the current release line, unist-util-visit@^5
,
compatible with Node.js 16.
Related
unist-util-visit-parents
— walk the tree with a stack of parentsunist-util-filter
— create a new tree with all nodes that pass a testunist-util-map
— create a new tree with all nodes mapped by a given functionunist-util-flatmap
— create a new tree by mapping (to an array) with the given functionunist-util-remove
— remove nodes from a tree that pass a testunist-util-select
— select nodes with CSS-like selectors
Contribute
See contributing.md
in syntax-tree/.github
for
ways to get started.
See support.md
for ways to get help.
This project has a code of conduct. By interacting with this repository, organization, or community you agree to abide by its terms.