fix(language-service): fix error of array-index out of bounds exception (#33928)

PR Close #33928
2019-11-27 03:11:28 +00:00
parent 5a227d8d7c
commit c5006e025f
2 changed files with 9 additions and 1 deletions
--- a/packages/language-service/src/typescript_symbols.ts
+++ b/packages/language-service/src/typescript_symbols.ts
@ -295,7 +295,8 @@ class TypeWrapper implements Symbol {
        if (nType) {
          // get the right tuple type by value, like 'var t: [number, string];'
          if (nType.isUnion()) {
-            return new TypeWrapper(nType.types[value], this.context);
+            // return undefined if array index out of bound.
+            return nType.types[value] && new TypeWrapper(nType.types[value], this.context);
          }
          return new TypeWrapper(nType, this.context);
        }