@speclynx/apidom-traverse

@speclynx/apidom-traverse provides traversal utilities for ApiDOM structures.

Installation

You can install this package via npm CLI by running the following command:

 $ npm install @speclynx/apidom-traverse

Usage

traverse

The core traversal function that walks an ApiDOM tree using visitors.

import { ObjectElement } from '@speclynx/apidom-datamodel';
import { traverse } from '@speclynx/apidom-traverse';

const element = new ObjectElement({ a: 'b' });

traverse(element, {
  enter(path) {
    console.log('entering:', path.node.element);
  },
  leave(path) {
    console.log('leaving:', path.node.element);
  },
});

traverseAsync

Async version of traverse that supports async visitors.

import { ObjectElement } from '@speclynx/apidom-datamodel';
import { traverseAsync } from '@speclynx/apidom-traverse';

const element = new ObjectElement({ a: 'b' });

await traverseAsync(element, {
  async enter(path) {
    await someAsyncOperation(path.node);
  },
});

Operations

Higher-level functions built on top of traverse for common use cases. All operations use data-first signatures: the element comes before the predicate/options.

filter

Finds all elements matching the predicate.

import { ObjectElement, isNumberElement } from '@speclynx/apidom-datamodel';
import { filter } from '@speclynx/apidom-traverse';

const element = new ObjectElement({ a: 'b', c: 2 });

filter(element, isNumberElement); // => [NumberElement<2>]

find

Find first element that satisfies the provided predicate.

import { ObjectElement, isNumberElement } from '@speclynx/apidom-datamodel';
import { find } from '@speclynx/apidom-traverse';

const element = new ObjectElement({ a: 'b', c: 2 });

find(element, isNumberElement); // => NumberElement<2>

findAtOffset

ApiDOM nodes can be associated with source maps. This function finds the most inner node at the given offset. If includeRightBound is set, also finds nodes that end at the given offset.

import { findAtOffset } from '@speclynx/apidom-traverse';

findAtOffset(elementWithSourceMaps, 3); // => returns most inner node at offset 3
findAtOffset(elementWithSourceMaps, { offset: 3, includeRightBound: true });

reject

Complement of filter. Finds all elements NOT matching the predicate.

import { ArrayElement, isNumberElement } from '@speclynx/apidom-datamodel';
import { reject } from '@speclynx/apidom-traverse';

const element = new ArrayElement([1, 'a']);

reject(element, isNumberElement); // => [ArrayElement, StringElement<'a'>]

some

Tests whether at least one element passes the predicate.

import { ArrayElement, isNumberElement } from '@speclynx/apidom-datamodel';
import { some } from '@speclynx/apidom-traverse';

const element = new ArrayElement([1, 'a']);

some(element, isNumberElement); // => true

forEach

Executes the callback on this element and all descendants.

import { ArrayElement } from '@speclynx/apidom-datamodel';
import { forEach } from '@speclynx/apidom-traverse';

const element = new ArrayElement([1, 'a']);

forEach(element, console.dir); // => prints ArrayElement, NumberElement, StringElement in this order

The execution of the callback can be controlled further by providing a predicate.

import { ArrayElement, isNumberElement } from '@speclynx/apidom-datamodel';
import { forEach } from '@speclynx/apidom-traverse';

const element = new ArrayElement([1, 'a']);

forEach(element, { callback: console.dir, predicate: isNumberElement }); // => prints NumberElement<1>

parents

Computes upwards edges from every child to its parent.

ObjectElement example

import { ObjectElement } from '@speclynx/apidom-datamodel';
import { parents } from '@speclynx/apidom-traverse';

const element = new ObjectElement({ key: 'value' });
const memberElement = element.getMember('key');
const { key: keyElement, value: valueElement } = memberElement;

const parentEdges = parents(element); // => WeakMap<ChildElement, ParentElement>

parentEdges.get(memberElement) === element; // => true
parentEdges.get(keyElement) === memberElement; // => true
parentEdges.get(valueElement) === memberElement; // => true

ArrayElement example

import { ArrayElement, StringElement } from '@speclynx/apidom-datamodel';
import { parents } from '@speclynx/apidom-traverse';

const itemElement1 = new StringElement('item1');
const itemElement2 = new StringElement('item2');
const element = new ArrayElement([itemElement1, itemElement2]);

const parentEdges = parents(element); // => WeakMap<ChildElement, ParentElement>

parentEdges.get(itemElement1) === element; // => true
parentEdges.get(itemElement2) === element; // => true

Path

The Path object is passed to visitor functions and provides context about the current node.

Properties

node - The current element being visited
parent - The parent container (array or element)
parentPath - The Path of the parent element
key - The key or index in the parent
index - Numeric index if inside an array (undefined otherwise)
inList - Whether the node is inside an array

Methods

skip() - Skip visiting children of this node
stop() - Stop all traversal
replaceWith(node) - Replace the current node
remove() - Remove the current node (in mutable mode)
isRoot() - Check if this is the root node
getAncestry() - Get all ancestor paths
getAncestorNodes() - Get all ancestor nodes
getPathKeys() - Get the path from root to current node
findParent(predicate) - Find first parent matching predicate
find(predicate) - Find self or parent matching predicate

Visitor Utilities

getNodeType

Returns the element type name for use in visitors.

import { StringElement } from '@speclynx/apidom-datamodel';
import { getNodeType } from '@speclynx/apidom-traverse';

getNodeType(new StringElement('hello')); // => 'StringElement'

mergeVisitors

Merges multiple visitors into a single visitor.

import { mergeVisitors } from '@speclynx/apidom-traverse';

const visitor1 = { StringElement(path) { /* ... */ } };
const visitor2 = { NumberElement(path) { /* ... */ } };

const merged = mergeVisitors([visitor1, visitor2]);