11.6.1.1 Static Semantics: Early Errors

IdentifierStart :: \ UnicodeEscapeSequence

如果 SV (UnicodeEscapeSequence) 不是 “$” 或 “_”，或者由 UnicodeIDStart 词法生成匹配的码点的 utf16 编码，则属于语法错误。

It is a Syntax Error if SV(UnicodeEscapeSequence) is none of “$”, or “_”, or the UTF16Encoding of a code point matched by the UnicodeIDStart lexical grammar production.

IdentifierPart :: \ UnicodeEscapeSequence

如果 SV(UnicodeEscapeSequence) 不是 “$”、”_” 中的任何一个，或者是 或 的 utf16 编码，或者 Unicode 码点的 utf16 编码，该码点将与 UnicodeIDContinue 词法生成相匹配，则属于语法错误。

It is a Syntax Error if SV(UnicodeEscapeSequence) is none of “$”, or “_”, or the UTF16Encoding of either or , or the UTF16Encoding of a Unicode code point that would be matched by the UnicodeIDContinue lexical grammar production.

11.6.1.2 Static Semantics: StringValue

IdentifierName ::
IdentifierStart
IdentifierName IdentifierPart

1. 返回由 IdentifierName 对应的代码单位序列组成的字符串值。在确定序列时，首先用\UnicodeEscapeSequence 所代表的码点代替任何 UnicodeEscapeSequence 的出现，然后将整个IdentifierName 的码点通过 UTF16Encoding 转换为每个码点的 code units（代码单元）。

   1. Return the String value consisting of the sequence of code units corresponding to IdentifierName. In determining the sequence any occurrences of \ UnicodeEscapeSequence are first replaced with the code point represented by the UnicodeEscapeSequence and then the code points of the entire IdentifierName are converted to code units by UTF16Encoding each code point.