Typescript Deep Dive by Basarat Ali Syed

TypeScript Deep Dive
AST Tip: SyntaxKind
SyntaxKind is defined as a const enum , here is a sample:
export const enum SyntaxKind {
Unknown,
EndOfFileToken,
SingleLineCommentTrivia,
// ... LOTS more
It's a const enum (a concept we covered previously) so that it gets inlined (e.g. ts.SyntaxKind.EndOfFileToken becomes 1 )
and we don't get a dereferencing cost when working with AST. However the compiler is compiled with --
preserveConstEnums compiler flag so that the enum is still available at runtime. So in JavaScript you can use
ts.SyntaxKind.EndOfFileToken if you want. Additionally you can convert these enum members to display strings using the
following function:
export function syntaxKindToName(kind: ts.SyntaxKind) {
return (ts).SyntaxKind[kind];
}
TIP: SyntaxKind enum
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