Commit

1 files changed, 58 insertions, 0 deletions

diff --git a/src/node_modules/es-abstract/2020/CodePointAt.js b/src/node_modules/es-abstract/2020/CodePointAt.js
new file mode 100644
index 0000000..a25f7b3
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+++ b/src/node_modules/es-abstract/2020/CodePointAt.js
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+'use strict';
+
+var GetIntrinsic = require('../GetIntrinsic');
+
+var $TypeError = GetIntrinsic('%TypeError%');
+var callBound = require('../helpers/callBound');
+var isLeadingSurrogate = require('../helpers/isLeadingSurrogate');
+var isTrailingSurrogate = require('../helpers/isTrailingSurrogate');
+
+var Type = require('./Type');
+var UTF16DecodeSurrogatePair = require('./UTF16DecodeSurrogatePair');
+
+var $charAt = callBound('String.prototype.charAt');
+var $charCodeAt = callBound('String.prototype.charCodeAt');
+
+// https://tc39.es/ecma262/2020/#sec-codepointat
+
+module.exports = function CodePointAt(string, position) {
+	if (Type(string) !== 'String') {
+		throw new $TypeError('Assertion failed: `string` must be a String');
+	}
+	var size = string.length;
+	if (position < 0 || position >= size) {
+		throw new $TypeError('Assertion failed: `position` must be >= 0, and < the length of `string`');
+	}
+	var first = $charCodeAt(string, position);
+	var cp = $charAt(string, position);
+	var firstIsLeading = isLeadingSurrogate(first);
+	var firstIsTrailing = isTrailingSurrogate(first);
+	if (!firstIsLeading && !firstIsTrailing) {
+		return {
+			'[[CodePoint]]': cp,
+			'[[CodeUnitCount]]': 1,
+			'[[IsUnpairedSurrogate]]': false
+		};
+	}
+	if (firstIsTrailing || (position + 1 === size)) {
+		return {
+			'[[CodePoint]]': cp,
+			'[[CodeUnitCount]]': 1,
+			'[[IsUnpairedSurrogate]]': true
+		};
+	}
+	var second = $charCodeAt(string, position + 1);
+	if (!isTrailingSurrogate(second)) {
+		return {
+			'[[CodePoint]]': cp,
+			'[[CodeUnitCount]]': 1,
+			'[[IsUnpairedSurrogate]]': true
+		};
+	}
+
+	return {
+		'[[CodePoint]]': UTF16DecodeSurrogatePair(first, second),
+		'[[CodeUnitCount]]': 2,
+		'[[IsUnpairedSurrogate]]': false
+	};
+};