refactor: Add default implementation for WorkerOptions (#14860)

This adds an implementation of `Default` for both `WorkerOptions` and
`BootstrapOptions`. Since both of these structs are rather big, this
should make it easier for people unfamiliar with the internals to focus
on the options relevant to them.

As a user of `deno_runtime` I feel like these should serve as good
defaults, getting people them started without having to tweak the
runtime. Additionally even if some changes are made, the usage of
`..Default::default()` will significantly help with code clarity and
verbosity.

1 files changed, 32 insertions, 1 deletions

diff --git a/runtime/worker_bootstrap.rs b/runtime/worker_bootstrap.rs
index 31e7c4382..8af78c21a 100644
--- a/runtime/worker_bootstrap.rs
+++ b/runtime/worker_bootstrap.rs
@@ -1,7 +1,12 @@
-use crate::ops::runtime::ppid;
+// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.
+
 use deno_core::serde_json;
 use deno_core::serde_json::json;
 use deno_core::ModuleSpecifier;
+use std::thread;
+
+use crate::colors;
+use crate::ops::runtime::ppid;
 
 /// Common bootstrap options for MainWorker & WebWorker
 #[derive(Clone)]
@@ -24,6 +29,32 @@ pub struct BootstrapOptions {
   pub inspect: bool,
 }
 
+impl Default for BootstrapOptions {
+  fn default() -> Self {
+    let cpu_count = thread::available_parallelism()
+      .map(|p| p.get())
+      .unwrap_or(1);
+
+    let runtime_version = env!("CARGO_PKG_VERSION").into();
+    let user_agent = format!("Deno/{}", runtime_version);
+
+    Self {
+      runtime_version,
+      user_agent,
+      cpu_count,
+      no_color: !colors::use_color(),
+      is_tty: colors::is_tty(),
+      enable_testing_features: Default::default(),
+      debug_flag: Default::default(),
+      ts_version: Default::default(),
+      location: Default::default(),
+      unstable: Default::default(),
+      inspect: Default::default(),
+      args: Default::default(),
+    }
+  }
+}
+
 impl BootstrapOptions {
   pub fn as_json(&self) -> String {
     let payload = json!({