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Commit Description:
add model solution
Commit Description:
add model solution
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node_modules/es5-ext/string/#/at.js
| 35 lines
| 1.0 KiB
| application/javascript
| JavascriptLexer
|
| r789 | // Based on: https://github.com/mathiasbynens/String.prototype.at | |||
| // Thanks @mathiasbynens ! | ||||
| "use strict"; | ||||
| var toInteger = require("../../number/to-integer") | ||||
| , validValue = require("../../object/valid-value"); | ||||
| module.exports = function (pos) { | ||||
| var str = String(validValue(this)), size = str.length, cuFirst, cuSecond, nextPos, len; | ||||
| pos = toInteger(pos); | ||||
| // Account for out-of-bounds indices | ||||
| // The odd lower bound is because the ToInteger operation is | ||||
| // going to round `n` to `0` for `-1 < n <= 0`. | ||||
| if (pos <= -1 || pos >= size) return ""; | ||||
| // Second half of `ToInteger` | ||||
| // eslint-disable-next-line no-bitwise | ||||
| pos |= 0; | ||||
| // Get the first code unit and code unit value | ||||
| cuFirst = str.charCodeAt(pos); | ||||
| nextPos = pos + 1; | ||||
| len = 1; | ||||
| if ( | ||||
| // Check if it’s the start of a surrogate pair | ||||
| cuFirst >= 0xd800 && | ||||
| cuFirst <= 0xdbff && // High surrogate | ||||
| size > nextPos // There is a next code unit | ||||
| ) { | ||||
| cuSecond = str.charCodeAt(nextPos); | ||||
| if (cuSecond >= 0xdc00 && cuSecond <= 0xdfff) len = 2; // Low surrogate | ||||
| } | ||||
| return str.slice(pos, pos + len); | ||||
| }; | ||||