| // Copyright 2019 Google, Inc. All rights reserved. |
| // This code is governed by the BSD license found in the LICENSE file. |
| /*--- |
| esid: prod-OptionalExpression |
| description: > |
| demonstrate syntax-based short-circuiting. |
| info: | |
| If the expression on the LHS of ?. evaluates to null/undefined, the RHS is |
| not evaluated |
| features: [optional-chaining] |
| ---*/ |
| |
| const a = undefined; |
| let x = 1; |
| |
| a?.[++x] // short-circuiting. |
| a?.b.c(++x).d; // long short-circuiting. |
| |
| undefined?.[++x] // short-circuiting. |
| undefined?.b.c(++x).d; // long short-circuiting. |
| |
| assert.sameValue(1, x); |
