| // Copyright (C) 2016 the V8 project authors. All rights reserved. |
| // This code is governed by the BSD license found in the LICENSE file. |
| /*--- |
| esid: sec-string.prototype.substr |
| es6id: B.2.3.1 |
| description: > |
| Behavior when input string contains a surrogate pair |
| info: | |
| [...] |
| 4. If length is undefined, let end be +∞; otherwise let end be ? |
| ToInteger(length). |
| [...] |
| 7. Let resultLength be min(max(end, 0), size - intStart). |
| 8. If resultLength ≤ 0, return the empty String "". |
| 9. Return a String containing resultLength consecutive code units from S |
| beginning with the code unit at index intStart. |
| ---*/ |
| |
| assert.sameValue('\ud834\udf06'.substr(0), '\ud834\udf06', 'start: 0'); |
| assert.sameValue('\ud834\udf06'.substr(1), '\udf06', 'start: 1'); |
| assert.sameValue('\ud834\udf06'.substr(2), '', 'start: 2'); |
| assert.sameValue('\ud834\udf06'.substr(0, 0), '', 'end: 0'); |
| assert.sameValue('\ud834\udf06'.substr(0, 1), '\ud834', 'end: 1'); |
| assert.sameValue('\ud834\udf06'.substr(0, 2), '\ud834\udf06', 'end: 2'); |