feat(repl): add "--eval-file" flag to execute a script file on startup (#14247)

This commit adds support for "--eval-file" in "deno repl" subcommand.

This flag can be used to pass paths or URLs to files, that will be executed
on REPL startup. All files will be executed in the same context as the REPL
(ie. as "plain old scripts", not ES modules), sharing the global scope.

This feature allows to implement custom REPLs on top of Deno's REPL.

1 files changed, 35 insertions, 0 deletions

diff --git a/cli/tools/repl/mod.rs b/cli/tools/repl/mod.rs
index b49c641c4..f0964ec4d 100644
--- a/cli/tools/repl/mod.rs
+++ b/cli/tools/repl/mod.rs
@@ -2,6 +2,7 @@
 
 use crate::proc_state::ProcState;
 use deno_core::error::AnyError;
+use deno_runtime::permissions::Permissions;
 use deno_runtime::worker::MainWorker;
 use rustyline::error::ReadlineError;
 
@@ -58,9 +59,24 @@ async fn read_line_and_poll(
   }
 }
 
+async fn read_eval_file(
+  ps: &ProcState,
+  eval_file: &str,
+) -> Result<String, AnyError> {
+  let specifier = deno_core::resolve_url_or_path(eval_file)?;
+
+  let file = ps
+    .file_fetcher
+    .fetch(&specifier, &mut Permissions::allow_all())
+    .await?;
+
+  Ok((*file.source).clone())
+}
+
 pub async fn run(
   ps: &ProcState,
   worker: MainWorker,
+  maybe_eval_files: Option<Vec<String>>,
   maybe_eval: Option<String>,
 ) -> Result<i32, AnyError> {
   let mut repl_session = ReplSession::initialize(worker).await?;
@@ -74,6 +90,25 @@ pub async fn run(
   let history_file_path = ps.dir.root.join("deno_history.txt");
   let editor = ReplEditor::new(helper, history_file_path);
 
+  if let Some(eval_files) = maybe_eval_files {
+    for eval_file in eval_files {
+      match read_eval_file(ps, &eval_file).await {
+        Ok(eval_source) => {
+          let output = repl_session
+            .evaluate_line_and_get_output(&eval_source)
+            .await?;
+          // only output errors
+          if let EvaluationOutput::Error(error_text) = output {
+            println!("error in --eval-file file {}. {}", eval_file, error_text);
+          }
+        }
+        Err(e) => {
+          println!("error in --eval-file file {}. {}", eval_file, e);
+        }
+      }
+    }
+  }
+
   if let Some(eval) = maybe_eval {
     let output = repl_session.evaluate_line_and_get_output(&eval).await?;
     // only output errors