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- /**
- * Fixes block-shadowed let/const bindings in Safari 10/11.
- * https://kangax.github.io/compat-table/es6/#test-let_scope_shadow_resolution
- */
- export default function({ types: t }) {
- return {
- name: "transform-safari-block-shadowing",
- visitor: {
- VariableDeclarator(path) {
- // the issue only affects let and const bindings:
- const kind = path.parent.kind;
- if (kind !== "let" && kind !== "const") return;
- // ignore non-block-scoped bindings:
- const block = path.scope.block;
- if (t.isFunction(block) || t.isProgram(block)) return;
- const bindings = t.getOuterBindingIdentifiers(path.node.id);
- for (const name of Object.keys(bindings)) {
- let scope = path.scope;
- // ignore parent bindings (note: impossible due to let/const?)
- if (!scope.hasOwnBinding(name)) continue;
- // check if shadowed within the nearest function/program boundary
- while ((scope = scope.parent)) {
- if (scope.hasOwnBinding(name)) {
- path.scope.rename(name);
- break;
- }
- if (t.isFunction(scope.block) || t.isProgram(scope.block)) {
- break;
- }
- }
- }
- },
- },
- };
- }
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