[ts] Allow optional binding pattern parameters within types/interfaces (#12227)

2020-10-21 08:16:43 -05:00
parent ddb7e05f07
commit d51aa6d761
8 changed files with 432 additions and 2 deletions
--- a/packages/babel-parser/src/plugins/typescript/index.js
+++ b/packages/babel-parser/src/plugins/typescript/index.js
@@ -2573,7 +2573,11 @@ export default (superClass: Class<Parser>): Class<Parser> =>
    // Allow type annotations inside of a parameter list.
    parseAssignableListItemTypes(param: N.Pattern) {
      if (this.eat(tt.question)) {
-        if (param.type !== "Identifier" && !this.state.isDeclareContext) {
+        if (
+          param.type !== "Identifier" &&
+          !this.state.isDeclareContext &&
+          !this.state.inType
+        ) {
          this.raise(param.start, TSErrors.PatternIsOptional);
        }