unist-util-visit
!Buildbuild-badgebuild
!Coveragecoverage-badgecoverage
!Downloadsdownloads-badgedownloads
!Sizesize-badgesize
!Sponsorssponsors-badgecollective
!Backersbackers-badgecollective
!Chatchat-badgechatunist utility to walk the tree.
Contents
* [`visit(tree[, test], visitor[, reverse])`](#visittree-test-visitor-reverse)
* [`CONTINUE`](#continue)
* [`EXIT`](#exit)
* [`SKIP`](#skip)
* [`Action`](#action)
* [`ActionTuple`](#actiontuple)
* [`BuildVisitor`](#buildvisitor)
* [`Index`](#index)
* [`Test`](#test)
* [`Visitor`](#visitor)
* [`VisitorResult`](#visitorresult)
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 useunist-util-visit-parents
vp if you care about the entire stack
of parents.Install
This package is ESM onlyesm. In Node.js (version 16+), install with npm:npm install unist-util-visit
In Deno with
esm.sh
esmsh:import {CONTINUE, EXIT, SKIP, visit} from 'https://esm.sh/unist-util-visit@5'
In browsers with
esm.sh
esmsh:<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 identifiersCONTINUE
api-continue,
EXIT
api-exit, SKIP
api-skip, and visit
api-visit.
There is no default export.visit(tree[, test], visitor[, reverse])
This function works exactly the same as unist-util-visit-parents
vp,
but Visitor
api-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
vp-action.ActionTuple
List with an action and an index (TypeScript type).
See ActionTuple
in unist-util-visit-parents
vp-action-tuple.BuildVisitor
Build a typed Visitor
function from a tree and a test (TypeScript type).
See BuildVisitor
in unist-util-visit-parents
vp-build-visitor.Index
Move to the sibling at index
next (TypeScript type).
See Index
in unist-util-visit-parents
vp-index.Test
unist-util-is
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
— found node
index
(number
orundefined
)
— index of `node` in `parent`
— parent of `node`
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
vp-visitor-result.Types
This package is fully typed with TypeScript. It exports the additional typesAction
api-action,
ActionTuple
api-action-tuple, BuildVisitor
api-build-visitor,
Index
api-index, Test
api-test, Visitor
api-visitor, and
VisitorResult
api-visitor-result.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
— walk the tree with a stack of parents
— create a new tree with all nodes that pass a test
— create a new tree with all nodes mapped by a given function
— create a new tree by mapping (to an array) with the given function
— remove nodes from a tree that pass a test
— select nodes with CSS-like selectors
Contribute
Seecontributing.md
contributing in syntax-tree/.github
health for
ways to get started.
See support.md
support for ways to get help.This project has a code of conductcoc. By interacting with this repository, organization, or community you agree to abide by its terms.