unist-utils-core

!OSS Lifecycle

A collection of commonly used (albeit enhanced) algorithms based on unist and unist-util-xxx.

Why yet another unist utility?

A few core unist-utils algorithms (combined with ES6), satisfy most of my needs. They are:
* test
* visit
* find
* select

But I wanted a more uniform API and enhanced functionality. Maybe you will like them too.

Installation

You can get the latest release using npm:

``
$ npm install unist-utils-core --save
`

Modifications / Enhancements

Node


Not having a strongly typed parent field was just frustrating.
Given that my parser already knows the parent, unist-util-parents was just to much overhead.
`
import {Node} from 'unist-utils-core';

let node: Node;
...
node.parent.children.find(n => Object.is(n, node));
`

Visit


unist-util-visit is nice, but has no ancestral info, and you can't pass an array of nodes.
unist-util-visit-children can pass an array of nodes, but incurs overhead with narrow applicability.
unist-util-visit-parents takes extra processing to determine a node's index in the list of children.
Also, I wanted an easy way to hook begin/end visitation of a node's children.
Optional support has been added for a caller defined context that can be passed to the Visitor.
`
import {visit} from 'unist-utils-core';

visit(tree.children, (node, idx, parents, ctx) => {
if (node) {
// Normal visitation of 'node'.
return whatever;
}
else if (idx === Number.MIN_SAFE_INTEGER) {
// beginning traversal of parents[parents.length-1].children
}
else if (idx === Number.MAX_SAFE_INTEGER) {
// finished traversal of parents[parents.length-1].children
}
});
`

Test


unist-util-is is a great core utility.
But I also needed a TestFunction that could return true/false, not just a type predicate.
And, I don't use anything except 'is.convert', and that just doesn't sound right. :-)
`
import {Test, test} from 'unist-utils-core';

if (test(node, (n) => !!n)) {
...
}
`

Find


unist-util-find is usefule, but doesn't use unist-util-is for it's tests (maybe because of the true/false thing mentioned above).
I also needed findAll and findAncestor.
`
import {find, findAll, findAncestor} from 'unist-utils-core';

findAll(tree, (node) => node.type === 'foo').map(n => whatever(n));
`

Select


unist-util-select may well be my favorite unist utility.
But, I use TypeScript and wanted to be able to type the return value(s).
`
import {select, selectAll} from 'unist-utils-core';

selectAll('loop', tree).filter(n => !n.forever);
``

Acknowledgements

Thanks to all the packages mentioned above.
If any of these ideas sound useful, feel free to merge them in and I'll phase these out.

MIT License

Copyright (c) 2020-2023 Frank Stock

Permission is hereby granted, free of charge, to any person obtaining a copy
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