Add NO_BUILD_SNAPSHOTS to speed up incremental builds (#3847)

1 files changed, 10 insertions, 0 deletions

diff --git a/cli/build.rs b/cli/build.rs
index ed04986a4..7e073c8ff 100644
--- a/cli/build.rs
+++ b/cli/build.rs
@@ -47,6 +47,16 @@ fn main() {
     deno_typescript::ts_version()
   );
 
+  // The generation of snapshots is slow and often unnecessary. Until we figure
+  // out how to speed it up, or avoid it when unnecessary, this env var provides
+  // an escape hatch for the impatient hacker in need of faster incremental
+  // builds.
+  // USE WITH EXTREME CAUTION
+  if env::var_os("NO_BUILD_SNAPSHOTS").is_some() {
+    println!("NO_BUILD_SNAPSHOTS is set, skipping snapshot building.");
+    return;
+  }
+
   let c = PathBuf::from(env::var_os("CARGO_MANIFEST_DIR").unwrap());
   let o = PathBuf::from(env::var_os("OUT_DIR").unwrap());