upgrade AST<->ESTree translation

[alexlamsl]

fixes #968

[kzc]

I attempted to vet this PR by running acorn on both sides of uglify-js minify while processing rollup-ts sources but it encountered errors:

--- a/test/release/rollup-ts.sh
+++ b/test/release/rollup-ts.sh
@@ -15,8 +15,12 @@ minify_in_situ() {
     for i in `find $DIRS -type f -name '*.ts' | grep -v '\.d\.ts'`
     do
         echo "$i"
-        node_modules/.bin/esbuild --loader=ts --target=node14 < "$i" \
-            | uglify-js $UGLIFY_OPTIONS -o "$i"
+        node_modules/.bin/esbuild --loader=ts --target=es2020 < "$i" \
+            | node_modules/.bin/acorn --ecma2020 --module \
+            | uglify-js -p spidermonkey $UGLIFY_OPTIONS -o spidermonkey \
+            | uglify-js -p spidermonkey \
+            | node_modules/.bin/acorn --ecma2020 --module \
+            | uglify-js -p spidermonkey -o "$i"
     done
 }

estree es2019 input works for this source file:

$ curl -s https://raw.githubusercontent.com/rollup/rollup/e9bedf202e4754caaa32d566c9eef0147e1ef3b9/cli/run/batchWarnings.ts | esbuild --loader=ts --target=es2019 | acorn --ecma2020 --module | uglify-js -p spidermonkey

but the equivalent estree es2020 input fails:

$ curl -s https://raw.githubusercontent.com/rollup/rollup/e9bedf202e4754caaa32d566c9eef0147e1ef3b9/cli/run/batchWarnings.ts | esbuild --loader=ts --target=es2020 | acorn --ecma2020 --module | uglify-js -p spidermonkey
ERROR: MOZ_TO_ME[node.type] is not a function

due to:

$ echo 'const id = warning.id || warning.loc?.file;' | node_modules/.bin/acorn --module --ecma2020 | uglify-js -p spidermonkey
ERROR: MOZ_TO_ME[node.type] is not a function

I can't make uglify-js accept the ESTree input for the following command regardless of esbuild target:

$ curl -s https://raw.githubusercontent.com/rollup/rollup/e9bedf202e4754caaa32d566c9eef0147e1ef3b9/cli/run/index.ts | esbuild --loader=ts --target=es2020 | acorn --ecma2020 --module | uglify-js -p spidermonkey
ERROR: MOZ_TO_ME[node.type] is not a function

due to:

$ echo 'async function a(){const {watch} = await import("./watch-cli");}' | node_modules/.bin/acorn --module --ecma2020 | uglify-js -p spidermonkey
ERROR: MOZ_TO_ME[node.type] is not a function

Feel free to takeover the patch above to further test and get it working. The number of steps in the verification pipeline may seem excessive but it's the only way I'm aware of to filter both the spidermonkey input and spidermonkey output for the same minify process through acorn. It also has the advantage of exercising uglify-js to parse its own spidermonkey output. Note that esbuild --target=es2020 is preferable to --target=node14 because of NodeJS-specific object spread/rest transforms in esbuild.

Edit: corrected the rollup-ts patch to use --target=es2020 instead of --target=es2019.

[kzc]

The following patch improves the usability of unknown ESTree node type errors:

--- a/lib/mozilla-ast.js
+++ b/lib/mozilla-ast.js
@@ -1160,7 +1160,14 @@
 
-    function from_moz(node) {
-        FROM_MOZ_STACK.push(node);
-        var ret = node != null ? MOZ_TO_ME[node.type](node) : null;
+    function from_moz(moz) {
+        FROM_MOZ_STACK.push(moz);
+        var native = null;
+        if (moz) {
+            if (HOP(MOZ_TO_ME, moz.type)) {
+                native = MOZ_TO_ME[moz.type](moz);
+            } else {
+                js_error("Unknown mozilla node type '" + moz.type + "' at position " + moz.start);
+            }
+        }
         FROM_MOZ_STACK.pop();
-        return ret;
+        return native;
     }

$ echo 'const id = warning.id || warning.loc?.file;' | node_modules/.bin/acorn --module --ecma2020 | uglify-js -p spidermonkey -p spidermonkey
ERROR: Unknown mozilla node type 'ChainExpression' at position 25

$ echo 'async function a(){const {watch} = await import("./watch-cli");}' | node_modules/.bin/acorn --module --ecma2020 | uglify-js -p spidermonkey
ERROR: Unknown mozilla node type 'ImportExpression' at position 41