refactor(@angular-devkit/build-optimizer): remove unused import purifier

Author: clydin

packages/angular_devkit/build_optimizer/src/build-optimizer/build-optimizer_spec.ts

@@ -58,7 +58,6 @@ describe('build-optimizer', () => {
       `;
       // tslint:disable:max-line-length
       const output = tags.oneLine`
-        /** PURE_IMPORTS_START _angular_core,tslib PURE_IMPORTS_END */
         ${imports}
         import { __extends } from "tslib";
         var ChangeDetectionStrategy = /*@__PURE__*/ (function (ChangeDetectionStrategy) {
@@ -93,7 +92,6 @@ describe('build-optimizer', () => {
 
     it('supports flagging module as side-effect free', () => {
       const output = tags.oneLine`
-        /** PURE_IMPORTS_START  PURE_IMPORTS_END */
         var RenderType_MdOption = /*@__PURE__*/ ɵcrt({ encapsulation: 2, styles: styles_MdOption });
       `;
       const input = tags.stripIndent`

packages/angular_devkit/build_optimizer/src/transforms/prefix-functions.ts

@@ -15,20 +15,8 @@ export function getPrefixFunctionsTransformer(): ts.TransformerFactory<ts.Source
     const transformer: ts.Transformer<ts.SourceFile> = (sf: ts.SourceFile) => {
 
       const topLevelFunctions = findTopLevelFunctions(sf);
-      const pureImports = findPureImports(sf);
-      const pureImportsComment = `* PURE_IMPORTS_START ${pureImports.join(',')} PURE_IMPORTS_END `;
 
       const visitor: ts.Visitor = (node: ts.Node): ts.Node => {
-
-        // Add the pure imports comment to the first node.
-        if (node.parent && node.parent.parent === undefined && node.pos === 0) {
-          const newNode = ts.addSyntheticLeadingComment(
-            node, ts.SyntaxKind.MultiLineCommentTrivia, pureImportsComment, true);
-
-          // Replace node with modified one.
-          return ts.visitEachChild(newNode, visitor, context);
-        }
-
         // Add pure function comment to top level functions.
         if (topLevelFunctions.has(node)) {
           const newNode = ts.addSyntheticLeadingComment(
@@ -109,28 +97,6 @@ export function findTopLevelFunctions(parentNode: ts.Node): Set<ts.Node> {
   return topLevelFunctions;
 }
 
-export function findPureImports(parentNode: ts.Node): string[] {
-  const pureImports: string[] = [];
-  ts.forEachChild(parentNode, cb);
-
-  function cb(node: ts.Node) {
-    if (node.kind === ts.SyntaxKind.ImportDeclaration
-      && (node as ts.ImportDeclaration).importClause) {
-
-      // Save the path of the import transformed into snake case and remove relative paths.
-      const moduleSpecifier = (node as ts.ImportDeclaration).moduleSpecifier as ts.StringLiteral;
-      const pureImport = moduleSpecifier.text
-        .replace(/[\/@\-]/g, '_')
-        .replace(/^\.+/, '');
-      pureImports.push(pureImport);
-    }
-
-    ts.forEachChild(node, cb);
-  }
-
-  return pureImports;
-}
-
 function hasPureComment(node: ts.Node) {
   if (!node) {
     return false;

packages/angular_devkit/build_optimizer/src/transforms/prefix-functions_spec.ts

@@ -15,45 +15,14 @@ const transform = (content: string) => transformJavascript(
   { content, getTransforms: [getPrefixFunctionsTransformer] }).content;
 
 describe('prefix-functions', () => {
-  const emptyImportsComment = '/** PURE_IMPORTS_START  PURE_IMPORTS_END */';
   const clazz = 'var Clazz = (function () { function Clazz() { } return Clazz; }());';
 
-  describe('pure imports', () => {
-    it('adds import list', () => {
-      const input = tags.stripIndent`
-        import { Injectable } from '@angular/core';
-        import { Something } from './relative/pure_import';
-        var foo = Injectable;
-        var bar = Something;
-      `;
-      const output = tags.stripIndent`
-        /** PURE_IMPORTS_START _angular_core,_relative_pure_import PURE_IMPORTS_END */
-        ${input}
-      `;
-
-      expect(tags.oneLine`${transform(input)}`).toEqual(tags.oneLine`${output}`);
-    });
-
-    it('adds import list even with no imports', () => {
-      const input = tags.stripIndent`
-        var foo = 42;
-      `;
-      const output = tags.stripIndent`
-        ${emptyImportsComment}
-        ${input}
-      `;
-
-      expect(tags.oneLine`${transform(input)}`).toEqual(tags.oneLine`${output}`);
-    });
-  });
-
   describe('pure functions', () => {
     it('adds comment to new calls', () => {
       const input = tags.stripIndent`
         var newClazz = new Clazz();
       `;
       const output = tags.stripIndent`
-        ${emptyImportsComment}
         var newClazz = /*@__PURE__*/ new Clazz();
       `;
 
@@ -65,7 +34,6 @@ describe('prefix-functions', () => {
         var newClazz = Clazz();
       `;
       const output = tags.stripIndent`
-        ${emptyImportsComment}
         var newClazz = /*@__PURE__*/ Clazz();
       `;
 
@@ -78,7 +46,6 @@ describe('prefix-functions', () => {
         var ClazzTwo = (function () { function Clazz() { } return Clazz; })();
       `;
       const output = tags.stripIndent`
-        ${emptyImportsComment}
         var Clazz = /*@__PURE__*/ (function () { function Clazz() { } return Clazz; }());
         var ClazzTwo = /*@__PURE__*/ (function () { function Clazz() { } return Clazz; })();
       `;
@@ -99,7 +66,6 @@ describe('prefix-functions', () => {
         };
       `;
       const output = tags.stripIndent`
-        ${emptyImportsComment}
         ${input}
       `;
 
@@ -118,7 +84,6 @@ describe('prefix-functions', () => {
         export { MyFunction };
       `;
       const output = tags.stripIndent`
-        ${emptyImportsComment}
         ${input}
       `;
 
@@ -137,7 +102,6 @@ describe('prefix-functions', () => {
         }
       `;
       const output = tags.stripIndent`
-        ${emptyImportsComment}
         ${input}
       `;
 
@@ -156,7 +120,6 @@ describe('prefix-functions', () => {
         };
       `;
       const output = tags.stripIndent`
-        ${emptyImportsComment}
         ${input}
       `;
 
@@ -172,7 +135,6 @@ describe('prefix-functions', () => {
         };
       `;
       const output = tags.stripIndent`
-        ${emptyImportsComment}
         ${input}
       `;