refactor: rewrite transform (#273)

Author: fisker

jest.config.js

@@ -15,7 +15,7 @@ export default {
   moduleNameMapper: {
     '^(\\.{1,2}/.*)\\.js$': '$1',
   },
-  coverageReporters: ['lcov', 'text-summary'],
+  coverageReporters: ['text', 'lcov', 'text-summary'],
   collectCoverage: !!process.env.ENABLE_COVERAGE,
   collectCoverageFrom: ['src/**/*.ts'],
   coverageThreshold: {

src/index.ts

@@ -1,21 +1,27 @@
 import type * as ng from '@angular/compiler';
-import type * as b from '@babel/types';
-import { Context } from './context.js';
-import { transform } from './transform.js';
+import transformComment from './transform-comment.js';
+import transformNode from './transform-node.js';
 import { transformTemplateBindings } from './transform-microsyntax.js';
-import type { NGNode, RawNGComment, NGMicrosyntax } from './types.js';
+import type {
+  NGNode,
+  RawNGComment,
+  NGMicrosyntax,
+  ParseResult,
+} from './types.js';
 import * as angularParser from './parser.js';
+import { type Context } from './context.js';
 
 function createParser(
-  parse: (input: string) => { ast: ng.AST; comments: RawNGComment[] },
+  parse: (text: string) => {
+    ast: ng.AST;
+    comments: RawNGComment[];
+    context: Context;
+  },
 ) {
-  return (input: string) => {
-    const { ast: rawNgAst, comments } = parse(input);
-    const context = new Context(input);
-    const ast = transform(rawNgAst, context) as NGNode;
-    ast.comments = comments.map((comment) =>
-      transform(comment, context),
-    ) as b.CommentLine[];
+  return (text: string) => {
+    const { ast: angularNode, comments, context } = parse(text);
+    const ast = transformNode(angularNode, context) as ParseResult;
+    ast.comments = comments.map((comment) => transformComment(comment));
     return ast;
   };
 }
@@ -28,9 +34,6 @@ export const parseInterpolationExpression = createParser(
   angularParser.parseInterpolationExpression,
 );
 export const parseAction = createParser(angularParser.parseAction);
-export const parseTemplateBindings = (input: string): NGMicrosyntax =>
-  transformTemplateBindings(
-    angularParser.parseTemplateBindings(input),
-    new Context(input),
-  );
+export const parseTemplateBindings = (text: string): NGMicrosyntax =>
+  transformTemplateBindings(angularParser.parseTemplateBindings(text));
 export type { NGMicrosyntax, NGNode };

src/parser.ts

@@ -6,6 +6,7 @@ import {
   type ParserError,
 } from '@angular/compiler';
 import { type RawNGComment } from './types.js';
+import { Context } from './context.js';
 
 const NG_PARSE_FAKE_LOCATION = 'angular-estree-parser';
 const NG_PARSE_TEMPLATE_BINDINGS_FAKE_PREFIX = 'NgEstreeParser';
@@ -23,11 +24,12 @@ function parse(
   text: string,
   parse: (text: string, parser: Parser) => ASTWithSource,
 ) {
+  const context = new Context(text);
   const parser = createParser();
   const { text: textToParse, comments } = extractComments(text, parser);
   const { ast, errors } = parse(textToParse, parser);
   assertAstErrors(errors);
-  return { ast, comments };
+  return { ast, comments, context };
 }
 
 function parseBinding(text: string) {
@@ -60,16 +62,18 @@ function parseInterpolationExpression(text: string) {
 }
 
 function parseTemplateBindings(text: string) {
+  const context = new Context(text);
   const parser = createParser();
-  const { templateBindings: ast, errors } = parser.parseTemplateBindings(
-    NG_PARSE_TEMPLATE_BINDINGS_FAKE_PREFIX,
-    text,
-    NG_PARSE_FAKE_LOCATION,
-    NG_PARSE_FAKE_ABSOLUTE_OFFSET,
-    NG_PARSE_FAKE_ABSOLUTE_OFFSET,
-  );
+  const { templateBindings: expressions, errors } =
+    parser.parseTemplateBindings(
+      NG_PARSE_TEMPLATE_BINDINGS_FAKE_PREFIX,
+      text,
+      NG_PARSE_FAKE_LOCATION,
+      NG_PARSE_FAKE_ABSOLUTE_OFFSET,
+      NG_PARSE_FAKE_ABSOLUTE_OFFSET,
+    );
   assertAstErrors(errors);
-  return ast;
+  return { expressions, context };
 }
 
 function assertAstErrors(errors: ParserError[]) {

src/transform-comment.ts

@@ -0,0 +1,14 @@
+import type { RawNGComment } from './types.js';
+import type { CommentLine } from '@babel/types';
+import { sourceSpanToLocationInformation } from './utils.js';
+
+function transformComment(comment: RawNGComment): CommentLine {
+  const { value, sourceSpan } = comment;
+  return {
+    type: 'CommentLine',
+    value,
+    ...sourceSpanToLocationInformation(sourceSpan),
+  };
+}
+
+export default transformComment;

src/transform-microsyntax.ts

@@ -4,12 +4,7 @@ import {
   VariableBinding as NGVariableBinding,
 } from '@angular/compiler';
 import { type Context } from './context.js';
-import {
-  type InputNode,
-  type OutputNode,
-  transform,
-  transformSpan,
-} from './transform.js';
+import transformNode from './transform-node.js';
 import type {
   NGMicrosyntax,
   NGMicrosyntaxAs,
@@ -22,12 +17,15 @@ import type {
   RawNGSpan,
 } from './types.js';
 import { NG_PARSE_TEMPLATE_BINDINGS_FAKE_PREFIX } from './parser.js';
-import { toLowerCamelCase } from './utils.js';
+import { toLowerCamelCase, transformSpan } from './utils.js';
 
-export function transformTemplateBindings(
-  rawTemplateBindings: ng.TemplateBinding[],
-  context: Context,
-): NGMicrosyntax {
+function transformTemplateBindings({
+  expressions: rawTemplateBindings,
+  context,
+}: {
+  expressions: ng.TemplateBinding[];
+  context: Context;
+}): NGMicrosyntax {
   rawTemplateBindings.forEach(fixTemplateBindingSpan);
 
   const [firstTemplateBinding] = rawTemplateBindings;
@@ -62,7 +60,7 @@ export function transformTemplateBindings(
       );
       const updateSpanEnd = <T extends NGNode>(node: T, end: number): T => ({
         ...node,
-        ...transformSpan({ start: node.start!, end }, context),
+        ...transformSpan({ start: node.start!, end }, context.text),
       });
       const updateExpressionAlias = (expression: NGMicrosyntaxExpression) => ({
         ...updateSpanEnd(expression, alias.end),
@@ -180,21 +178,21 @@ export function transformTemplateBindings(
     }
   }
 
-  function _t<T extends OutputNode>(n: InputNode) {
-    return transform(n, context) as T & RawNGSpan;
+  function _t<T extends NGNode>(n: ng.AST) {
+    return transformNode(n, context) as T;
   }
 
-  function _c<T extends OutputNode>(
+  function _c<T extends NGNode>(
     t: T['type'],
     n: Partial<T>,
     span: RawNGSpan,
     stripSpaces = true,
   ) {
     return {
       type: t,
-      ...transformSpan(span, context, stripSpaces),
+      ...transformSpan(span, context.text, { processSpan: stripSpaces }),
       ...n,
-    } as T & { start: number; end: number; range: [number, number] };
+    } as T;
   }
 
   function removePrefix(string: string) {
@@ -271,3 +269,5 @@ export function transformTemplateBindings(
     };
   }
 }
+
+export { transformTemplateBindings };