diff options
Diffstat (limited to 'src/node_modules/es-abstract/2017/StringGetOwnProperty.js')
-rw-r--r-- | src/node_modules/es-abstract/2017/StringGetOwnProperty.js | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/src/node_modules/es-abstract/2017/StringGetOwnProperty.js b/src/node_modules/es-abstract/2017/StringGetOwnProperty.js new file mode 100644 index 0000000..f8db320 --- /dev/null +++ b/src/node_modules/es-abstract/2017/StringGetOwnProperty.js @@ -0,0 +1,48 @@ +'use strict'; + +var GetIntrinsic = require('../GetIntrinsic'); + +var $TypeError = GetIntrinsic('%TypeError%'); + +var callBound = require('../helpers/callBound'); +var $charAt = callBound('String.prototype.charAt'); +var $stringToString = callBound('String.prototype.toString'); + +var CanonicalNumericIndexString = require('./CanonicalNumericIndexString'); +var IsInteger = require('./IsInteger'); +var IsPropertyKey = require('./IsPropertyKey'); +var Type = require('./Type'); + +var isNegativeZero = require('is-negative-zero'); + +// https://ecma-international.org/ecma-262/8.0/#sec-stringgetownproperty + +module.exports = function StringGetOwnProperty(S, P) { + var str; + if (Type(S) === 'Object') { + try { + str = $stringToString(S); + } catch (e) { /**/ } + } + if (Type(str) !== 'String') { + throw new $TypeError('Assertion failed: `S` must be a boxed string object'); + } + if (!IsPropertyKey(P)) { + throw new $TypeError('Assertion failed: IsPropertyKey(P) is not true'); + } + if (Type(P) !== 'String') { + return void undefined; + } + var index = CanonicalNumericIndexString(P); + var len = str.length; + if (typeof index === 'undefined' || !IsInteger(index) || isNegativeZero(index) || index < 0 || len <= index) { + return void undefined; + } + var resultStr = $charAt(S, index); + return { + '[[Configurable]]': false, + '[[Enumerable]]': true, + '[[Value]]': resultStr, + '[[Writable]]': false + }; +}; |