[New] ES2015+: add Canonicalize

.gitattributes

@@ -1,3 +1,4 @@
+/helpers/caseFolding.json	linguist-generated=true
 /es2015.js	spackled linguist-generated=true
 /es2016.js	spackled linguist-generated=true
 /es2017.js	spackled linguist-generated=true
@@ -48,6 +49,7 @@
 /2016/ArraySpeciesCreate.js	spackled linguist-generated=true
 /2016/Call.js	spackled linguist-generated=true
 /2016/CanonicalNumericIndexString.js	spackled linguist-generated=true
+/2016/Canonicalize.js	spackled linguist-generated=true
 /2016/CharacterRange.js	spackled linguist-generated=true
 /2016/CompletePropertyDescriptor.js	spackled linguist-generated=true
 /2016/CreateDataProperty.js	spackled linguist-generated=true
@@ -173,6 +175,7 @@
 /2017/ArraySpeciesCreate.js	spackled linguist-generated=true
 /2017/Call.js	spackled linguist-generated=true
 /2017/CanonicalNumericIndexString.js	spackled linguist-generated=true
+/2017/Canonicalize.js	spackled linguist-generated=true
 /2017/CharacterRange.js	spackled linguist-generated=true
 /2017/CompletePropertyDescriptor.js	spackled linguist-generated=true
 /2017/CompletionRecord.js	spackled linguist-generated=true
@@ -301,6 +304,7 @@
 /2018/ArraySpeciesCreate.js	spackled linguist-generated=true
 /2018/Call.js	spackled linguist-generated=true
 /2018/CanonicalNumericIndexString.js	spackled linguist-generated=true
+/2018/Canonicalize.js	spackled linguist-generated=true
 /2018/CharacterRange.js	spackled linguist-generated=true
 /2018/CompletePropertyDescriptor.js	spackled linguist-generated=true
 /2018/CompletionRecord.js	spackled linguist-generated=true
@@ -436,6 +440,7 @@
 /2019/AsyncIteratorClose.js	spackled linguist-generated=true
 /2019/Call.js	spackled linguist-generated=true
 /2019/CanonicalNumericIndexString.js	spackled linguist-generated=true
+/2019/Canonicalize.js	spackled linguist-generated=true
 /2019/CharacterRange.js	spackled linguist-generated=true
 /2019/CompletePropertyDescriptor.js	spackled linguist-generated=true
 /2019/CompletionRecord.js	spackled linguist-generated=true
@@ -582,6 +587,7 @@
 /2020/AsyncIteratorClose.js	spackled linguist-generated=true
 /2020/Call.js	spackled linguist-generated=true
 /2020/CanonicalNumericIndexString.js	spackled linguist-generated=true
+/2020/Canonicalize.js	spackled linguist-generated=true
 /2020/CharacterRange.js	spackled linguist-generated=true
 /2020/CompletePropertyDescriptor.js	spackled linguist-generated=true
 /2020/CompletionRecord.js	spackled linguist-generated=true
@@ -734,6 +740,7 @@
 /2021/BinaryXor.js	spackled linguist-generated=true
 /2021/Call.js	spackled linguist-generated=true
 /2021/CanonicalNumericIndexString.js	spackled linguist-generated=true
+/2021/Canonicalize.js	spackled linguist-generated=true
 /2021/CharacterRange.js	spackled linguist-generated=true
 /2021/CompletePropertyDescriptor.js	spackled linguist-generated=true
 /2021/CompletionRecord.js	spackled linguist-generated=true
@@ -924,6 +931,7 @@
 /2022/ByteListEqual.js	spackled linguist-generated=true
 /2022/Call.js	spackled linguist-generated=true
 /2022/CanonicalNumericIndexString.js	spackled linguist-generated=true
+/2022/Canonicalize.js	spackled linguist-generated=true
 /2022/CharacterRange.js	spackled linguist-generated=true
 /2022/ClearKeptObjects.js	spackled linguist-generated=true
 /2022/CodePointAt.js	spackled linguist-generated=true

2015/Canonicalize.js

@@ -0,0 +1,55 @@
+'use strict';
+
+var GetIntrinsic = require('get-intrinsic');
+
+var $TypeError = GetIntrinsic('%TypeError%');
+
+var callBound = require('call-bind/callBound');
+var has = require('has');
+
+var $charCodeAt = callBound('String.prototype.charCodeAt');
+var $toUpperCase = callBound('String.prototype.toUpperCase');
+
+var Type = require('./Type');
+
+var caseFolding = require('../helpers/caseFolding');
+
+// https://262.ecma-international.org/6.0/#sec-runtime-semantics-canonicalize-ch
+
+module.exports = function Canonicalize(ch, IgnoreCase, Unicode) {
+	if (Type(ch) !== 'String') {
+		throw new $TypeError('Assertion failed: `ch` must be a character');
+	}
+
+	if (Type(IgnoreCase) !== 'Boolean' || Type(Unicode) !== 'Boolean') {
+		throw new $TypeError('Assertion failed: `IgnoreCase` and `Unicode` must be Booleans');
+	}
+
+	if (!IgnoreCase) {
+		return ch; // step 1
+	}
+
+	if (Unicode) { // step 2
+		if (has(caseFolding.C, ch)) {
+			return caseFolding.C[ch];
+		}
+		if (has(caseFolding.S, ch)) {
+			return caseFolding.S[ch];
+		}
+		return ch; // step 2.b
+	}
+
+	var u = $toUpperCase(ch); // step 2
+
+	if (u.length !== 1) {
+		return ch; // step 3
+	}
+
+	var cu = u; // step 4
+
+	if ($charCodeAt(ch, 0) >= 128 && $charCodeAt(cu, 0) < 128) {
+		return ch; // step 5
+	}
+
+	return cu;
+};