1 files changed, 98 insertions, 0 deletions
diff --git a/node_modules/sucrase/dist/esm/identifyShadowedGlobals.js b/node_modules/sucrase/dist/esm/identifyShadowedGlobals.js
new file mode 100644
index 0000000..f953633
--- /dev/null
+++ b/node_modules/sucrase/dist/esm/identifyShadowedGlobals.js
@@ -0,0 +1,98 @@
+import {
+  isBlockScopedDeclaration,
+  isFunctionScopedDeclaration,
+  isNonTopLevelDeclaration,
+} from "./parser/tokenizer";
+
+import {TokenType as tt} from "./parser/tokenizer/types";
+
+
+/**
+ * Traverse the given tokens and modify them if necessary to indicate that some names shadow global
+ * variables.
+ */
+export default function identifyShadowedGlobals(
+  tokens,
+  scopes,
+  globalNames,
+) {
+  if (!hasShadowedGlobals(tokens, globalNames)) {
+    return;
+  }
+  markShadowedGlobals(tokens, scopes, globalNames);
+}
+
+/**
+ * We can do a fast up-front check to see if there are any declarations to global names. If not,
+ * then there's no point in computing scope assignments.
+ */
+// Exported for testing.
+export function hasShadowedGlobals(tokens, globalNames) {
+  for (const token of tokens.tokens) {
+    if (
+      token.type === tt.name &&
+      !token.isType &&
+      isNonTopLevelDeclaration(token) &&
+      globalNames.has(tokens.identifierNameForToken(token))
+    ) {
+      return true;
+    }
+  }
+  return false;
+}
+
+function markShadowedGlobals(
+  tokens,
+  scopes,
+  globalNames,
+) {
+  const scopeStack = [];
+  let scopeIndex = scopes.length - 1;
+  // Scopes were generated at completion time, so they're sorted by end index, so we can maintain a
+  // good stack by going backwards through them.
+  for (let i = tokens.tokens.length - 1; ; i--) {
+    while (scopeStack.length > 0 && scopeStack[scopeStack.length - 1].startTokenIndex === i + 1) {
+      scopeStack.pop();
+    }
+    while (scopeIndex >= 0 && scopes[scopeIndex].endTokenIndex === i + 1) {
+      scopeStack.push(scopes[scopeIndex]);
+      scopeIndex--;
+    }
+    // Process scopes after the last iteration so we can make sure we pop all of them.
+    if (i < 0) {
+      break;
+    }
+
+    const token = tokens.tokens[i];
+    const name = tokens.identifierNameForToken(token);
+    if (scopeStack.length > 1 && !token.isType && token.type === tt.name && globalNames.has(name)) {
+      if (isBlockScopedDeclaration(token)) {
+        markShadowedForScope(scopeStack[scopeStack.length - 1], tokens, name);
+      } else if (isFunctionScopedDeclaration(token)) {
+        let stackIndex = scopeStack.length - 1;
+        while (stackIndex > 0 && !scopeStack[stackIndex].isFunctionScope) {
+          stackIndex--;
+        }
+        if (stackIndex < 0) {
+          throw new Error("Did not find parent function scope.");
+        }
+        markShadowedForScope(scopeStack[stackIndex], tokens, name);
+      }
+    }
+  }
+  if (scopeStack.length > 0) {
+    throw new Error("Expected empty scope stack after processing file.");
+  }
+}
+
+function markShadowedForScope(scope, tokens, name) {
+  for (let i = scope.startTokenIndex; i < scope.endTokenIndex; i++) {
+    const token = tokens.tokens[i];
+    if (
+      (token.type === tt.name || token.type === tt.jsxName) &&
+      tokens.identifierNameForToken(token) === name
+    ) {
+      token.shadowsGlobal = true;
+    }
+  }
+}