74 lines
2.1 KiB
JavaScript
74 lines
2.1 KiB
JavaScript
import { without, flatten } from 'lodash';
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import u from 'unist-builder';
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import mdastDefinitions from 'mdast-util-definitions';
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/**
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* Raw markdown may contain image references or link references. Because there
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* is no way to maintain these references within the Slate AST, we convert image
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* and link references to standard images and links by putting their url's
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* inline. The definitions are then removed from the document.
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*
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* For example, the following markdown:
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*
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* ```
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* ![alpha][bravo]
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*
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* [bravo]: http://example.com/example.jpg
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* ```
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*
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* Yields:
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*
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* ```
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* 
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* ```
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*
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*/
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export default function remarkSquashReferences() {
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return getTransform;
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function getTransform(node) {
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const getDefinition = mdastDefinitions(node);
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return transform.call(null, getDefinition, node);
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}
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function transform(getDefinition, node) {
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/**
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* Bind the `getDefinition` function to `transform` and recursively map all
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* nodes.
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*/
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const boundTransform = transform.bind(null, getDefinition);
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const children = node.children ? node.children.map(boundTransform) : node.children;
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/**
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* Combine reference and definition nodes into standard image and link
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* nodes.
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*/
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if (['imageReference', 'linkReference'].includes(node.type)) {
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const type = node.type === 'imageReference' ? 'image' : 'link';
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const definition = getDefinition(node.identifier);
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if (definition) {
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const { title, url } = definition;
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return u(type, { title, url, alt: node.alt }, children);
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}
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const pre = u('text', node.type === 'imageReference' ? '![' : '[');
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const post = u('text', ']');
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const nodes = children || [u('text', node.alt)];
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return [pre, ...nodes, post];
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}
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/**
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* Remove definition nodes and filter the resulting null values from the
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* filtered children array.
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*/
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if (node.type === 'definition') {
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return null;
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}
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const filteredChildren = without(children, null);
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return { ...node, children: flatten(filteredChildren) };
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}
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}
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