${valIdentifier ? `${valIdentifier} - The Book` : \"The Book\"}

[{"_1":2,"_3":-5,"_4":-5},"loaderData",{"_5":6,"_7":8,"_9":10},"actionData","errors","root",{"_157":158,"_159":160},"routes/_app.x.$handle.$name",{"_11":12,"_13":14,"_15":16,"_18":19,"_17":-7,"_119":-5,"_20":120,"_22":121,"_122":123,"_124":125,"_25":126,"_24":-5,"_127":-5,"_128":-5,"_129":53,"_130":131,"_132":44,"_133":-5,"_134":-5,"_135":136},"routes/_app.x.$handle.$name.branch.$branch.code.$",{"_11":12,"_13":14,"_15":16,"_17":-7,"_18":19,"_20":21,"_22":23,"_24":-7,"_25":26,"_27":-5,"_28":-5,"_29":-5,"_30":-5,"_31":-5},"handle","tmcw","name","book","branchName","main","version","path","","project",{"_33":61,"_13":14,"_45":62,"_63":-5,"_64":53,"_65":66,"_67":66,"_68":69,"_70":19,"_71":72,"_73":-5,"_74":53,"_75":-5,"_76":-5,"_77":78,"_79":80,"_81":82,"_83":84,"_85":86,"_87":-5,"_88":89,"_90":89,"_91":92,"_93":92,"_94":92,"_95":89,"_96":89,"_97":98,"_99":100,"_101":102,"_103":53},"tree",[56],"file","contents",[32],"upstream","pull","ahead","behind","envVars",{"_33":34,"_13":35,"_36":37,"_38":-5,"_39":40,"_41":42,"_43":44,"_45":46,"_17":47,"_48":49,"_50":51,"_52":53,"_54":-5,"_18":55},"id","8883b514-05fa-11f1-95cc-42dde27851f2","main.ts","fileId","f3c6aeba-05ed-11f1-8ba5-42dde27851f2","parentId","branchId","f3c3b0f2-05ed-11f1-8ba5-42dde27851f2","branchVersion",58,"latest",true,"createdAt",["D",1770670901500],57,"fileType","http","content","import Cerebras from \"npm:@cerebras/cerebras_cloud_sdk\";\nimport { sqlite } from \"https://esm.town/v/std/sqlite@14-main/main.ts\";\n\ninterface ValFile {\n name: string;\n path: string;\n type: \"file\" | \"directory\" | \"interval\" | \"http\" | \"email\" | \"script\";\n}\n\ninterface FileContent {\n name: string;\n path: string;\n code: string;\n chapterTitle?: string;\n explanation?: string;\n}\n\ninterface ValInfo {\n id: string;\n name: string;\n description?: string;\n}\n\n// Initialize database\nawait sqlite.execute(`\n CREATE TABLE IF NOT EXISTS file_cache (\n val_identifier TEXT NOT NULL,\n file_path TEXT NOT NULL,\n code_hash TEXT NOT NULL,\n chapter_title TEXT,\n explanation TEXT,\n created_at INTEGER DEFAULT (strftime('%s', 'now')),\n PRIMARY KEY (val_identifier, file_path)\n )\n`);\n\nawait sqlite.execute(`\n CREATE INDEX IF NOT EXISTS idx_val_file ON file_cache(val_identifier, file_path)\n`);\n\nfunction hashCode(str: string): string {\n let hash = 0;\n for (let i = 0; i < str.length; i++) {\n const char = str.charCodeAt(i);\n hash = ((hash << 5) - hash) + char;\n hash = hash & hash;\n }\n return hash.toString(36);\n}\n\nasync function getCachedData(\n valIdentifier: string,\n filePath: string,\n codeHash: string,\n): Promise<{ chapterTitle?: string; explanation?: string } | null> {\n const result = await sqlite.execute({\n sql: `SELECT chapter_title, explanation FROM file_cache\n WHERE val_identifier = ? AND file_path = ? AND code_hash = ?`,\n args: [valIdentifier, filePath, codeHash],\n });\n\n if (result.rows.length > 0) {\n const row = result.rows[0] as {\n chapter_title: string;\n explanation: string;\n };\n return {\n chapterTitle: row.chapter_title,\n explanation: row.explanation,\n };\n }\n return null;\n}\n\nasync function setCachedData(\n valIdentifier: string,\n filePath: string,\n codeHash: string,\n chapterTitle?: string,\n explanation?: string,\n): Promise {\n await sqlite.execute({\n sql: `INSERT OR REPLACE INTO file_cache\n (val_identifier, file_path, code_hash, chapter_title, explanation)\n VALUES (?, ?, ?, ?, ?)`,\n args: [\n valIdentifier,\n filePath,\n codeHash,\n chapterTitle || null,\n explanation || null,\n ],\n });\n}\n\nasync function fetchValByAlias(\n handle: string,\n valName: string,\n): Promise {\n const res = await fetch(\n `https://api.val.town/v2/alias/vals/${handle}/${valName}`,\n );\n if (!res.ok) {\n throw new Error(`Failed to fetch val: ${res.status} ${res.statusText}`);\n }\n return res.json();\n}\n\nasync function fetchValFiles(valId: string): Promise {\n const res = await fetch(`https://api.val.town/v2/vals/${valId}/files?path`);\n if (!res.ok) {\n throw new Error(\n `Failed to fetch files: ${res.status} ${res.statusText} ${await res\n .text()}`,\n );\n }\n const data = await res.json();\n return data.data || [];\n}\n\nasync function fetchFileContent(valId: string, path: string): Promise {\n const res = await fetch(\n `https://api.val.town/v2/vals/${valId}/files/content?path=${\n encodeURIComponent(path)\n }`,\n );\n if (!res.ok) {\n return `// Failed to load content: ${res.status}`;\n }\n const data = await res.text();\n return data || \"\";\n}\n\nasync function generateChapterTitles(\n valIdentifier: string,\n files: FileContent[],\n): Promise {\n const apiKey = Deno.env.get(\"CEREBRAS_API_KEY\");\n if (!apiKey) {\n return files.map((f) => f.path);\n }\n\n const cachedTitles: (string | null)[] = await Promise.all(\n files.map(async (f) => {\n const hash = hashCode(f.code);\n const cached = await getCachedData(valIdentifier, f.path, hash);\n return cached?.chapterTitle || null;\n }),\n );\n\n if (cachedTitles.every((t) => t !== null)) {\n return cachedTitles as string[];\n }\n\n const client = new Cerebras({ apiKey });\n\n const codeSnippets = files\n .map(\n (f, i) =>\n `File ${i + 1} (${f.path}):\\n\\`\\`\\`\\n${f.code.slice(0, 1500)}\\n\\`\\`\\``,\n )\n .join(\"\\n\\n\");\n\n const prompt =\n `You are creating chapter titles for a programming book. Each chapter corresponds to a code file. Generate creative, evocative chapter titles that capture the essence of what each file does - like chapters in a novel about code.\n\nHere are the code files:\n\n${codeSnippets}\n\nGenerate one title per file, in the same order. Keep titles concise (2-6 words). Be creative and literary, not just technical descriptions.`;\n\n const schema = {\n type: \"object\",\n properties: {\n titles: {\n type: \"array\",\n items: { type: \"string\" },\n },\n },\n required: [\"titles\"],\n additionalProperties: false,\n };\n\n try {\n const completion = await client.chat.completions.create({\n model: \"llama3.3-70b\",\n messages: [{ role: \"user\", content: prompt }],\n temperature: 0.7,\n response_format: {\n type: \"json_schema\",\n json_schema: {\n name: \"chapter_titles\",\n strict: true,\n schema: schema,\n },\n },\n });\n\n const content = completion.choices?.[0]?.message?.content || \"\";\n\n if (content) {\n const result = JSON.parse(content);\n if (\n result.titles && Array.isArray(result.titles) &&\n result.titles.length === files.length\n ) {\n await Promise.all(\n files.map(async (f, i) => {\n const hash = hashCode(f.code);\n await setCachedData(\n valIdentifier,\n f.path,\n hash,\n result.titles[i],\n undefined,\n );\n }),\n );\n return result.titles;\n }\n }\n\n return files.map((f) => f.path);\n } catch (e) {\n console.error(\"Error generating chapter titles:\", e);\n return files.map((f) => f.path);\n }\n}\n\nasync function generateExplanation(\n valIdentifier: string,\n file: FileContent,\n): Promise {\n const apiKey = Deno.env.get(\"CEREBRAS_API_KEY\");\n if (!apiKey) {\n return \"\";\n }\n\n const hash = hashCode(file.code);\n const cached = await getCachedData(valIdentifier, file.path, hash);\n if (cached?.explanation) {\n return cached.explanation;\n }\n\n const client = new Cerebras({ apiKey });\n\n const prompt =\n `You are writing prose explanations for a programming book. Explain what this code does in 4-6 paragraphs of engaging, literary prose.\n\nIMPORTANT: Reference specific parts of the code using markdown links in this format: [description](/${file.path}:START-END) where START and END are line numbers (1-indexed).\n\nFor example:\n- [the main function](/${file.path}:15-20) - references lines 15-20\n- [database initialization](/${file.path}:5-8) - references lines 5-8\n- [error handling](/${file.path}:42-42) - references a single line\n\nUse these links frequently to connect your prose to specific code sections. Make the prose literary and engaging, like you're telling a story about what the code accomplishes.\n\nHere is the code for ${file.path}:\n\n\\`\\`\\`\n${file.code}\n\\`\\`\\`\n\nWrite 2-4 paragraphs explaining this code with markdown links to specific line ranges:`;\n\n const schema = {\n type: \"object\",\n properties: {\n explanation: {\n type: \"string\",\n },\n },\n required: [\"explanation\"],\n additionalProperties: false,\n };\n\n try {\n const completion = await client.chat.completions.create({\n model: \"llama3.3-70b\",\n messages: [{ role: \"user\", content: prompt }],\n temperature: 0.7,\n response_format: {\n type: \"json_schema\",\n json_schema: {\n name: \"code_explanation\",\n strict: true,\n schema: schema,\n },\n },\n });\n\n const content = completion.choices?.[0]?.message?.content || \"\";\n\n if (content) {\n const result = JSON.parse(content);\n if (result.explanation) {\n await setCachedData(\n valIdentifier,\n file.path,\n hash,\n file.chapterTitle,\n result.explanation,\n );\n return result.explanation;\n }\n }\n\n return \"\";\n } catch (e) {\n console.error(\"Error generating explanation:\", e);\n return \"\";\n }\n}\n\nfunction filterCodeFiles(files: ValFile[]): ValFile[] {\n return files.filter(\n (f) => f.type !== \"directory\" && /\\.(ts|tsx|js|jsx)$/.test(f.name),\n );\n}\n\nfunction escapeHtml(str: string): string {\n return str\n .replace(/&/g, \"&\")\n .replace(//g, \">\")\n .replace(/\"/g, \""\");\n}\n\nfunction parseMarkdownLinks(text: string): string {\n return text.replace(\n /\\[([^\\]]+)\\]\$\\/[^:]+:(\\d+)-(\\d+)\$/g,\n (match, linkText, start, end) => {\n return `${\n escapeHtml(linkText)\n }`;\n },\n );\n}\n\nfunction buildScriptTag(): string {\n // Build this as a plain string to avoid template literal escaping issues\n const lines = [\n \"\",\n ];\n return lines.join(\"\\n\");\n}\n\nfunction renderPage(\n valIdentifier: string,\n chapters: FileContent[],\n selectedIndex: number = 0,\n error?: string,\n): string {\n const selected = chapters[selectedIndex];\n\n const chapterItems = chapters\n .map(\n (ch, i) => `\n \n ${String(i + 1).padStart(2, \"0\")}\n ${\n escapeHtml(ch.chapterTitle || ch.path)\n }\n \n `,\n )\n .join(\"\");\n\n const middleContent = selected?.explanation\n ? `

${\n selected.explanation.split(\"\\n\\n\").map((para) =>\n `

${parseMarkdownLinks(para)}

`\n ).join(\"\")\n }

`\n : selected\n ? `

Loading explanation...

`\n : error\n ? `

${escapeHtml(error)}

`\n : `

Select a chapter to read

`;\n\n // Raw code in a hidden div, empty code element to be filled by JS\n const codeContent = selected\n ? `

`\n : `

Select a file to view its code

`;\n\n const scriptTag = buildScriptTag();\n\n return `\n\n\n \n \n ${valIdentifier ? `${valIdentifier} - The Book` : \"The Book\"}\n\n \n \n \n\n \n\n\n

\n\n

\n ${middleContent}\n

\n\n

\n ${codeContent}\n

\n\n ${scriptTag}\n\n`;\n}\n\nexport default async function (req: Request): Promise {\n const url = new URL(req.url);\n const valParam = url.searchParams.get(\"val\") || \"\";\n const chapterParam = url.searchParams.get(\"chapter\");\n const selectedIndex = chapterParam ? parseInt(chapterParam, 10) : 0;\n\n let chapters: FileContent[] = [];\n let error: string | undefined;\n\n if (valParam) {\n const parts = valParam.split(\"/\");\n if (parts.length === 2) {\n const [handle, valName] = parts;\n try {\n const valInfo = await fetchValByAlias(handle, valName);\n const files = await fetchValFiles(valInfo.id);\n const codeFiles = filterCodeFiles(files);\n\n chapters = await Promise.all(\n codeFiles.map(async (f) => ({\n name: f.name,\n path: f.path,\n code: await fetchFileContent(valInfo.id, f.path),\n })),\n );\n\n const titles = await generateChapterTitles(valParam, chapters);\n chapters = chapters.map((ch, i) => ({\n ...ch,\n chapterTitle: titles[i],\n }));\n\n if (chapters[selectedIndex]) {\n const explanation = await generateExplanation(\n valParam,\n chapters[selectedIndex],\n );\n chapters[selectedIndex].explanation = explanation;\n }\n } catch (e) {\n error = e instanceof Error ? e.message : \"Failed to fetch val\";\n }\n } else {\n error = \"Invalid val identifier. Use format: handle/valName\";\n }\n }\n\n const validIndex = Math.max(0, Math.min(selectedIndex, chapters.length - 1));\n\n return new Response(renderPage(valParam, chapters, validIndex, error), {\n headers: { \"Content-Type\": \"text/html\" },\n });\n}\n","deleted",false,"label",[35],{"_33":34,"_13":35,"_36":37,"_38":-5,"_39":40,"_41":42,"_43":44,"_45":57,"_17":47,"_48":49,"_50":51,"_52":53,"_54":-5,"_58":59,"_18":60},["D",1770670901500],"children",[],[35],"f3c36976-05ed-11f1-8ba5-42dde27851f2",["D",1770665498007],"deletedAt","legacyEnvVars","privacy","public","httpPrivacy","description","Code like a book","imageUrl","userId","19892fed-baf3-41fb-a5cc-96c80e95edec","pinnedFileId","pinPreview","pinMigrated","screenshotVersion","likeCount",0,"orgId","f407f111-fdbb-4126-923f-44aed4d9e9ad","tursoName","f3c3697605ed11f18ba542dde27851f2","tursoHostname","f3c3697605ed11f18ba542dde27851f2-val-town.aws-us-east-2.turso.io","tursoMeasuredAt",["D",1789521640046],"pinned","userPerm","r","valPerm","blobPerm","rw","emailPerm","sqlitePerm","projectPerm","telemetryPerm","user",{"_11":12,"_118":114},"org",{"_11":12,"_112":-5,"_113":114,"_71":72,"_115":116,"_117":53},"branch",{"_17":42,"_13":16,"_33":40,"_104":61,"_105":-5,"_106":-5,"_107":-5,"_108":-5,"_109":-5,"_110":14,"_111":12},"isOwned","projectId","forkedBranchId","forkedBranchVersion","forkedProjectPrivacy","forkedProjectId","forkedProjectOrgId","projectName","userHandle","displayName","avatar","https://imagedelivery.net/iHX6Ovru0O7AjmyT5yZRoA/7935dc1b-7699-4095-366a-2e9103307501/square512?exp=1789588799&sig=39d8f16ee939a1abae6c1744554950aec75b527f146f1c3d65fc31b51edc55b3","tier","pro","canRestrictVals","profileImageUrl","adoptOrgId",{"_33":61,"_13":14,"_45":152,"_63":-5,"_64":53,"_65":66,"_67":66,"_68":69,"_70":19,"_71":72,"_73":-5,"_74":53,"_75":-5,"_76":-5,"_77":78,"_79":80,"_81":82,"_83":84,"_85":153,"_87":-5,"_88":89,"_90":89,"_91":92,"_93":92,"_94":92,"_95":89,"_96":89,"_97":154,"_99":155,"_101":156,"_103":53},[149],"files",[149],"counts",{"_139":78,"_140":141,"_142":78,"_31":143,"_144":145},[137],"upstreamProject","upstreamBranch","emptyEnvVars","flags",[],"hasHttpFiles","grants","orgs","customDomains",{},{"_33":34,"_13":35,"_36":37,"_38":-5,"_39":40,"_41":42,"_43":44,"_45":46,"_17":47,"_48":49,"_50":51,"_52":53,"_54":-5,"_18":138},[35],"pulls","branches",1,"forks",{"_146":141,"_148":78},"connections",{"_146":78,"_147":78},"count","unfilledCount","emptyCount",{"_33":34,"_13":35,"_36":37,"_38":-5,"_39":40,"_41":42,"_43":44,"_45":57,"_17":47,"_48":49,"_50":51,"_52":53,"_54":-5,"_58":150,"_18":151},[],[35],["D",1770665498007],["D",1789521640046],{"_11":12,"_118":114},{"_11":12,"_112":-5,"_113":114,"_71":72,"_115":116,"_117":53},{"_17":42,"_13":16,"_33":40,"_104":61,"_105":-5,"_106":-5,"_107":-5,"_108":-5,"_109":-5,"_110":14,"_111":12},"ctx",{"_97":-5,"_134":190,"_191":192,"_193":194,"_195":53,"_196":53,"_197":53,"_198":44,"_199":-5,"_200":-7,"_201":-7,"_202":78,"_203":53,"_204":53,"_205":-5,"_206":53,"_207":53,"_208":53,"_209":-5},"ENV",{"_161":162,"_163":164,"_165":16,"_166":167,"_168":169,"_170":171,"_172":173,"_174":175,"_176":177,"_178":179,"_180":181,"_182":183,"_184":185,"_186":187,"_188":189},"REACT_APP_SENTRY_DSN","https://586020d86f05489db63a554690acf1e9@o1398359.ingest.sentry.io/6724499","RENDER_GIT_COMMIT","fdb67791413f4386b4dbf18f354029a617f6160f","RENDER_GIT_BRANCH","POSTHOG_API_TOKEN","phc_nmoyuAkStEZuUp69rYlg1DZgrIt19Gx0Y4Hwf8tGgJP","POSTHOG_API_HOST","https://wart.val.town","WEB_API_TEMPLATE","https://{val}.web.val.run","APP_URL","https://www.val.town","MODULE_URL","https://esm.town","VANITY_WEB_API_TEMPLATE","https://{label}.val.run/","DENOLS_URL","https://lsp.val.town","NODE_ENV","production","CLOUDFLARE_TURNSTILE_SITE_KEY","0x4AAAAAACtaIZJH7s9rBMZ6","GOOGLE_CLIENT_ID","875989696899-jtsqkhlbdv5jrlsk8631p7ipjg3c6o62.apps.googleusercontent.com","STRIPE_PUBLISHABLE_KEY","pk_live_51N2zvWEpZTTLipIkVEwXrUG9AT0yeOOEYxszarZT1jpsZV58Ly6wlg3SltZpHN26CUalOBmUSY7adQRQiSkCZz2500qSXNkf8Y","API_URL","https://api.val.town",[],"preferencesKeybindings","default","preferencesTheme","light","preferencesFixers","preferencesCopilot","preferencesSelectionAi","preferencesCloseBrackets","preferencesChatPanelState","preferencesDprint","preferencesDenofmt","notificationCount","flagDenols","isBusinessOrgMember","businessOrgHandle","isBusinessOrgAdmin","isHigherTownieTier","navCollapsed","currentOrgId"]