45 lines
1.2 KiB
JavaScript
45 lines
1.2 KiB
JavaScript
'use strict';
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import util from 'util';
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const YOUTUBE_WATCH = 'https://youtu.be/%s';
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const GRAPH_NODE = ' "%s" [label="%s", URL="%s", fontcolor=blue]';
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const GRAPH_LINK = ' "%s" -> "%s"';
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/**
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* Escape double quotes in a string.
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*/
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const escapeQuotes = str => str.replace(/"/g, '\\"');
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/**
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* Convert a graph of videos to the DOT format.
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*
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* @param nodes Nodes of the graph.
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* @param next For each node, list of next neighbors.
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* @param [title=identity] Function giving the name of each node.
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* @param [url=none] Function given the URL of each node, or an empty string
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* if a node has no URL.
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* @return DOT representation of the graph.
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*/
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export const graphToDOT = (nodes, next) =>
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{
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// Convert nodes
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const nodesStr = Object.entries(nodes).map(([id, {title}]) =>
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{
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const url = util.format(YOUTUBE_WATCH, id);
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return util.format(GRAPH_NODE, id, escapeQuotes(title), url);
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}).join('\n');
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// Convert edges
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const nextStr = Object.entries(next).map(([id, neighbors]) =>
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Array.from(neighbors)
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.map(neighbor => util.format(GRAPH_LINK, id, neighbor))
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.join('\n')
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).join('\n');
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return `digraph youtube {
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${nodesStr}
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${nextStr}
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}`;
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};
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