| // Copyright (C) 2015 the V8 project authors. All rights reserved. |
| // This code is governed by the BSD license found in the LICENSE file. |
| /*--- |
| es6id: 21.1.3.18 |
| description: > |
| Returns based on coerced values of position. |
| info: | |
| 21.1.3.18 String.prototype.startsWith ( searchString [ , position ] ) |
| |
| ... |
| 9. Let pos be ToInteger(position). (If position is undefined, this step |
| produces the value 0). |
| 10. ReturnIfAbrupt(pos). |
| 11. Let len be the number of elements in S. |
| 12. Let start be min(max(pos, 0), len). |
| 13. Let searchLength be the number of elements in searchStr. |
| 14. If searchLength+start is greater than len, return false. |
| 15. If the sequence of elements of S starting at start of length searchLength |
| is the same as the full element sequence of searchStr, return true. |
| 16. Otherwise, return false. |
| ... |
| ---*/ |
| |
| var str = 'The future is cool!'; |
| |
| assert(str.startsWith('The future', NaN), 'NaN coerced to 0'); |
| assert(str.startsWith('The future', null), 'null coerced to 0'); |
| assert(str.startsWith('The future', false), 'false coerced to 0'); |
| assert(str.startsWith('The future', ''), '"" coerced to 0'); |
| assert(str.startsWith('The future', '0'), '"0" coerced to 0'); |
| assert(str.startsWith('The future', undefined), 'undefined coerced to 0'); |
| assert(str.startsWith('The future', 0.4), '0.4 coerced to 0'); |
| |
| assert.sameValue( |
| str.startsWith('The future', true), false, |
| 'true coerced to 1' |
| ); |
| assert.sameValue(str.startsWith('The future', '1'), false, '"1" coerced to 1'); |
| assert.sameValue(str.startsWith('The future', 1.4), false, '1.4 coerced to 1'); |