unist-util-is
Advanced tools
Package description
The unist-util-is npm package is a utility library for working with Unist nodes. Unist (Universal Syntax Tree) is part of the unified ecosystem, which provides a way to work with syntax trees for content such as Markdown, HTML, or plain text. unist-util-is specifically helps in testing and filtering nodes in these trees based on certain conditions.
Test nodes with a condition
This feature allows you to test if a node matches a specific type or condition. In the example, `is` is used to check if the root node is a 'leaf' (which it isn't), and then if the first child of the root is a 'leaf' (which it is).
const is = require('unist-util-is');
const u = require('unist-builder');
const tree = u('root', [
u('leaf', 'first leaf'),
u('node', [u('leaf', 'nested leaf')])
]);
const test = is(tree, 'leaf'); // false
const testLeaf = is(tree.children[0], 'leaf'); // trueFilter nodes by type
This feature demonstrates how to filter nodes by type using `is` in combination with `unist-util-select`. It selects all 'leaf' nodes from the tree and filters them to ensure they are of type 'leaf'.
const is = require('unist-util-is');
const u = require('unist-builder');
const select = require('unist-util-select');
const tree = u('root', [
u('leaf', 'first leaf'),
u('node', [u('leaf', 'nested leaf')])
]);
const leaves = select.selectAll('leaf', tree).filter(node => is(node, 'leaf'));This package is similar to unist-util-is in that it is used to work with Unist nodes. However, unist-util-visit focuses on visiting nodes within a tree, optionally filtering nodes, and applying a function to each node. It differs from unist-util-is by providing traversal capabilities rather than just testing or filtering.
unist-util-select is used to select nodes from a Unist tree using CSS-like selectors. It complements unist-util-is by providing a way to retrieve nodes based on complex queries, whereas unist-util-is is more focused on testing nodes against specified conditions.
Readme
Unist utility to check if a node passes a test.
npm:
npm install unist-util-is
var is = require('unist-util-is')
var node = {type: 'strong'}
var parent = {type: 'paragraph', children: [node]}
function test(node, n) {
return n === 5
}
is() // => false
is(null, {children: []}) // => false
is(null, node) // => true
is('strong', node) // => true
is('emphasis', node) // => false
is(node, node) // => true
is({type: 'paragraph'}, parent) // => true
is({type: 'strong'}, parent) // => false
is(test, node) // => false
is(test, node, 4, parent) // => false
is(test, node, 5, parent) // => true
is(test, node[, index, parent[, context]])test (Function, string, Object, or Array.<Test>, optional)
— When not given, checks if node is a Node.
When string, works like passing function (node) {return node.type === test}.
When array, checks any one of the subtests pass.
When object, checks that all keys in test are in node,
and that they have (strictly) equal valuesnode (Node) — Node to check. false is returnedindex (number, optional) — Position of node in parentparent (Node, optional) — Parent of nodecontext (*, optional) — Context object to invoke test withboolean — Whether test passed and node is a Node (object
with type set to non-empty string).
function test(node[, index, parent])node (Node) — Node to testindex (number?) — Position of node in parentparent (Node?) — Parent of node* — The to is given context.
boolean? — Whether node matches.
unist-util-find-after
— Find a node after another nodeunist-util-find-before
— Find a node before another nodeunist-util-find-all-after
— Find all nodes after another nodeunist-util-find-all-before
— Find all nodes before another nodeunist-util-find-all-between
— Find all nodes between two nodesunist-util-find
— Find nodes matching a predicateunist-util-filter
— Create a new tree with nodes that pass a checkunist-util-remove
— Remove nodes from treeSee contributing.md in syntax-tree/unist for ways to get
started.
This organisation has a Code of Conduct. By interacting with this repository, organisation, or community you agree to abide by its terms.
FAQs
unist utility to check if a node passes a test
The npm package unist-util-is receives a total of 11,367,092 weekly downloads. As such, unist-util-is popularity was classified as popular.
We found that unist-util-is demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 2 open source maintainers collaborating on the project.
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