Plato on Github
Report Home
node_modules/es5-ext/string/#/at.js
Maintainability
54.40
Lines of code
30
Difficulty
16.29
Estimated Errors
0.20
Function weight
By Complexity
By SLOC
// 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` pos = 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); };