feat(cli): `deno init --lib` (#22499)

Closes #22287

Co-authored-by: Asher Gomez <ashersaupingomez@gmail.com>
Co-authored-by: David Sherret <dsherret@gmail.com>

1 files changed, 134 insertions, 42 deletions

diff --git a/cli/tools/init/mod.rs b/cli/tools/init/mod.rs
index fb2e6e7af..23b14e17c 100644
--- a/cli/tools/init/mod.rs
+++ b/cli/tools/init/mod.rs
@@ -4,33 +4,11 @@ use crate::args::InitFlags;
 use crate::colors;
 use deno_core::anyhow::Context;
 use deno_core::error::AnyError;
+use deno_core::serde_json::json;
 use log::info;
 use std::io::Write;
 use std::path::Path;
 
-fn create_file(
-  dir: &Path,
-  filename: &str,
-  content: &str,
-) -> Result<(), AnyError> {
-  let path = dir.join(filename);
-  if path.exists() {
-    info!(
-      "ℹ️ {}",
-      colors::gray(format!("Skipped creating {filename} as it already exists"))
-    );
-    Ok(())
-  } else {
-    let mut file = std::fs::OpenOptions::new()
-      .write(true)
-      .create_new(true)
-      .open(path)
-      .with_context(|| format!("Failed to create {filename} file"))?;
-    file.write_all(content.as_bytes())?;
-    Ok(())
-  }
-}
-
 pub fn init_project(init_flags: InitFlags) -> Result<(), AnyError> {
   let cwd =
     std::env::current_dir().context("Can't read current working directory.")?;
@@ -42,15 +20,82 @@ pub fn init_project(init_flags: InitFlags) -> Result<(), AnyError> {
     cwd
   };
 
-  let main_ts = include_str!("./templates/main.ts");
-  create_file(&dir, "main.ts", main_ts)?;
+  if init_flags.lib {
+    // Extract the directory name to use as the project name
+    let project_name = dir
+      .file_name()
+      .unwrap_or_else(|| dir.as_os_str())
+      .to_str()
+      .unwrap();
+
+    create_file(
+      &dir,
+      "mod.ts",
+      r#"export function add(a: number, b: number): number {
+  return a + b;
+}
+"#,
+    )?;
+    create_file(
+      &dir,
+      "mod_test.ts",
+      r#"import { assertEquals } from "jsr:@std/assert";
+import { add } from "./mod.ts";
+
+Deno.test(function addTest() {
+  assertEquals(add(2, 3), 5);
+});
+"#,
+    )?;
+
+    create_json_file(
+      &dir,
+      "deno.json",
+      &json!({
+        "name": project_name,
+        "version": "1.0.0",
+        "exports": "./mod.ts",
+        "tasks": {
+          "dev": "deno test --watch mod.ts"
+        }
+      }),
+    )?;
+  } else {
+    create_file(
+      &dir,
+      "main.ts",
+      r#"export function add(a: number, b: number): number {
+  return a + b;
+}
+
+// Learn more at https://deno.land/manual/examples/module_metadata#concepts
+if (import.meta.main) {
+  console.log("Add 2 + 3 =", add(2, 3));
+}
+"#,
+    )?;
+    create_file(
+      &dir,
+      "main_test.ts",
+      r#"import { assertEquals } from "jsr:@std/assert";
+import { add } from "./main.ts";
 
-  create_file(
-    &dir,
-    "main_test.ts",
-    include_str!("./templates/main_test.ts"),
-  )?;
-  create_file(&dir, "deno.json", include_str!("./templates/deno.json"))?;
+Deno.test(function addTest() {
+  assertEquals(add(2, 3), 5);
+});
+"#,
+    )?;
+
+    create_json_file(
+      &dir,
+      "deno.json",
+      &json!({
+        "tasks": {
+          "dev": "deno run --watch main.ts"
+        }
+      }),
+    )?;
+  }
 
   info!("✅ {}", colors::green("Project initialized"));
   info!("");
@@ -60,16 +105,63 @@ pub fn init_project(init_flags: InitFlags) -> Result<(), AnyError> {
     info!("  cd {}", dir);
     info!("");
   }
-  info!("  {}", colors::gray("# Run the program"));
-  info!("  deno run main.ts");
-  info!("");
-  info!(
-    "  {}",
-    colors::gray("# Run the program and watch for file changes")
-  );
-  info!("  deno task dev");
-  info!("");
-  info!("  {}", colors::gray("# Run the tests"));
-  info!("  deno test");
+  if init_flags.lib {
+    info!("  {}", colors::gray("# Run the tests"));
+    info!("  deno test");
+    info!("");
+    info!(
+      "  {}",
+      colors::gray("# Run the tests and watch for file changes")
+    );
+    info!("  deno task dev");
+    info!("");
+    info!("  {}", colors::gray("# Publish to JSR (dry run)"));
+    info!("  deno publish --dry-run");
+  } else {
+    info!("  {}", colors::gray("# Run the program"));
+    info!("  deno run main.ts");
+    info!("");
+    info!(
+      "  {}",
+      colors::gray("# Run the program and watch for file changes")
+    );
+    info!("  deno task dev");
+    info!("");
+    info!("  {}", colors::gray("# Run the tests"));
+    info!("  deno test");
+  }
   Ok(())
 }
+
+fn create_json_file(
+  dir: &Path,
+  filename: &str,
+  value: &deno_core::serde_json::Value,
+) -> Result<(), AnyError> {
+  let mut text = deno_core::serde_json::to_string_pretty(value)?;
+  text.push('\n');
+  create_file(dir, filename, &text)
+}
+
+fn create_file(
+  dir: &Path,
+  filename: &str,
+  content: &str,
+) -> Result<(), AnyError> {
+  let path = dir.join(filename);
+  if path.exists() {
+    info!(
+      "ℹ️ {}",
+      colors::gray(format!("Skipped creating {filename} as it already exists"))
+    );
+    Ok(())
+  } else {
+    let mut file = std::fs::OpenOptions::new()
+      .write(true)
+      .create_new(true)
+      .open(path)
+      .with_context(|| format!("Failed to create {filename} file"))?;
+    file.write_all(content.as_bytes())?;
+    Ok(())
+  }
+}