Implemented basic search, alloc space issues

find-path.js

 const https = require('https')
 
+const REQ_LIMIT = 10
+
 const [source, target] = process.argv.slice(2)
 if (!(source && target)) throw new Error('Usage: node find-path.js source target')
 
 // TODO: find the shortest path from `source` to `target`
+const source_link = "https://en.wikipedia.org/wiki/" + source
+const target_link = "https://en.wikipedia.org/wiki/" + target
+
+// check source and target links to make sure they are real
+
+let visited = new Map()
+let curr_checking = []
+let next_checking = []
+
+curr_checking.push([source_link, source_link])
+
+const find_wiki_url = (contents) => {
+    const split_contents = contents.split('<a href="')
+    split_contents.shift()
+    let urls = []
+    for (const splat of split_contents) {
+        let possible_url = splat.split('"')[0]
+        if (possible_url.startsWith('/wiki/') && !possible_url.includes(':')) {
+            urls.push("https://en.wikipedia.org" + possible_url.split('#')[0])
+        }
+    }
+    return urls
+} 
+
+const post_process = () => {
+    let url_list = []
+    let parent = visited.get(target_link)
+    while (parent && parent != source_link) {
+        url_list.push(parent)
+        parent = visited.get(parent)
+    }
+    url_list.push(source_link)
+    url_list.reverse()
+    for (const url of url_list) {
+        const page = url.split('https://en.wikipedia.org/wiki/')[0]
+        console.log(page)
+    }
+    process.exit()
+}
+
+const search_link = (resolve) => {
+    let next_set, next_link, parent
+    do {
+        next_set = curr_checking.pop()
+        if (!next_set) {
+            resolve()
+            return
+        }
+        next_link = next_set[0]
+        parent = next_set[1]
+        if (next_link == target_link) {
+            console.log('yay!')
+            visited.set(next_link, parent)
+            post_process()
+            resolve()
+            return
+        }
+    } while (visited.has(next_link))
+    
+    //console.log(next_link)
+    visited.set(next_link, parent)
+    https.get(next_link, res => {
+        res.setEncoding('utf8')
+        let data = ""
+        res.on('data', chunk => {
+            data += chunk
+        })
+        res.on('end', () => {
+            let urls = find_wiki_url(data)
+            urls = urls.map(x => [x, parent])
+            next_checking.push(...urls)
+            search_link(resolve)
+        })
+    })
+}
+
+const parallel_search = () => {
+    let promises = []
+    for (let i = 0; i < REQ_LIMIT; i++) {
+        const aPromise = new Promise((resolve, reject) => {
+            search_link(resolve)
+        })
+        promises.push(aPromise)
+    }
+    return promises
+}
+
+const search_level = () => {
+    let promises = parallel_search()
+    Promise.all(promises).then(() => {
+        console.log('next', next_checking.length, (new Set(next_checking.map(x => x[0]))).size)
+
+        curr_checking = next_checking
+        next_checking = []
+    }).then(() => search_level())
+}
+
+search_level()
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