From 702d6bfe8f177adfc9ed65609e328f1e90a24466 Mon Sep 17 00:00:00 2001
From: Andrew Scott <atscott@google.com>
Date: Tue, 17 Nov 2020 13:00:11 -0800
Subject: [PATCH] refactor(compiler-cli): use keySpan for output event lookup
 (#39515)

PR #39665 added the `keySpan` to the output field access so we no longer
need to get there from the call expression and can instead just find the
node we want directly.

PR Close #39515
---
 .../typecheck/src/template_symbol_builder.ts  | 19 ++++------
 .../ngtsc/typecheck/src/type_check_block.ts   | 37 ++-----------------
 2 files changed, 11 insertions(+), 45 deletions(-)

diff --git a/packages/compiler-cli/src/ngtsc/typecheck/src/template_symbol_builder.ts b/packages/compiler-cli/src/ngtsc/typecheck/src/template_symbol_builder.ts
index 2cd6d2c746..00a1b32988 100644
--- a/packages/compiler-cli/src/ngtsc/typecheck/src/template_symbol_builder.ts
+++ b/packages/compiler-cli/src/ngtsc/typecheck/src/template_symbol_builder.ts
@@ -18,7 +18,6 @@ import {DirectiveSymbol, DomBindingSymbol, ElementSymbol, ExpressionSymbol, Inpu
 import {ExpressionIdentifier, findAllMatchingNodes, findFirstMatchingNode, hasExpressionIdentifier} from './comments';
 import {TemplateData} from './context';
 import {isAccessExpression} from './ts_util';
-import {TcbDirectiveOutputsOp} from './type_check_block';
 
 /**
  * Generates and caches `Symbol`s for various template structures for a given component.
@@ -169,9 +168,9 @@ export class SymbolBuilder {
     // Outputs are a `ts.CallExpression` that look like one of the two:
     // * _outputHelper(_t1["outputField"]).subscribe(handler);
     // * _t1.addEventListener(handler);
-    const node = findFirstMatchingNode(
-        this.typeCheckBlock, {withSpan: eventBinding.sourceSpan, filter: ts.isCallExpression});
-    if (node === null) {
+    const outputFieldAccess = findFirstMatchingNode(
+        this.typeCheckBlock, {withSpan: eventBinding.keySpan, filter: isAccessExpression});
+    if (outputFieldAccess === null) {
       return null;
     }
 
@@ -181,12 +180,12 @@ export class SymbolBuilder {
     }
 
     if (consumer instanceof TmplAstTemplate || consumer instanceof TmplAstElement) {
-      if (!ts.isPropertyAccessExpression(node.expression) ||
-          node.expression.name.text !== 'addEventListener') {
+      if (!ts.isPropertyAccessExpression(outputFieldAccess) ||
+          outputFieldAccess.name.text !== 'addEventListener') {
         return null;
       }
 
-      const addEventListener = node.expression.name;
+      const addEventListener = outputFieldAccess.name;
       const tsSymbol = this.getTypeChecker().getSymbolAtLocation(addEventListener);
       const tsType = this.getTypeChecker().getTypeAtLocation(addEventListener);
       const positionInShimFile = this.getShimPositionForNode(addEventListener);
@@ -207,11 +206,9 @@ export class SymbolBuilder {
         }],
       };
     } else {
-      const outputFieldAccess = TcbDirectiveOutputsOp.decodeOutputCallExpression(node);
-      if (outputFieldAccess === null) {
+      if (!ts.isElementAccessExpression(outputFieldAccess)) {
         return null;
       }
-
       const tsSymbol =
           this.getTypeChecker().getSymbolAtLocation(outputFieldAccess.argumentExpression);
       if (tsSymbol === undefined) {
@@ -225,7 +222,7 @@ export class SymbolBuilder {
       }
 
       const positionInShimFile = this.getShimPositionForNode(outputFieldAccess);
-      const tsType = this.getTypeChecker().getTypeAtLocation(node);
+      const tsType = this.getTypeChecker().getTypeAtLocation(outputFieldAccess);
       return {
         kind: SymbolKind.Output,
         bindings: [{
diff --git a/packages/compiler-cli/src/ngtsc/typecheck/src/type_check_block.ts b/packages/compiler-cli/src/ngtsc/typecheck/src/type_check_block.ts
index 9ad75894a9..55713439b9 100644
--- a/packages/compiler-cli/src/ngtsc/typecheck/src/type_check_block.ts
+++ b/packages/compiler-cli/src/ngtsc/typecheck/src/type_check_block.ts
@@ -902,39 +902,6 @@ export class TcbDirectiveOutputsOp extends TcbOp {
 
     return null;
   }
-
-  /**
-   * Outputs are a `ts.CallExpression` that look like one of the two:
-   *  - `_outputHelper(_t1["outputField"]).subscribe(handler);`
-   *  - `_t1.addEventListener(handler);`
-   * This method reverses the operations to create a call expression for a directive output.
-   * It unpacks the given call expression and returns the original element access (i.e.
-   * `_t1["outputField"]` in the example above). Returns `null` if the given call expression is not
-   * the expected structure of an output binding
-   */
-  static decodeOutputCallExpression(node: ts.CallExpression): ts.ElementAccessExpression|null {
-    // `node.expression` === `_outputHelper(_t1["outputField"]).subscribe` or `_t1.addEventListener`
-    if (!ts.isPropertyAccessExpression(node.expression) ||
-        node.expression.name.text === 'addEventListener') {
-      // `addEventListener` outputs do not have an `ElementAccessExpression` for the output field.
-      return null;
-    }
-
-    if (!ts.isCallExpression(node.expression.expression)) {
-      return null;
-    }
-
-    // `node.expression.expression` === `_outputHelper(_t1["outputField"])`
-    if (node.expression.expression.arguments.length === 0) {
-      return null;
-    }
-
-    const [outputFieldAccess] = node.expression.expression.arguments;
-    if (!ts.isElementAccessExpression(outputFieldAccess)) {
-      return null;
-    }
-    return outputFieldAccess;
-  }
 }
 
 /**
@@ -984,8 +951,10 @@ class TcbUnclaimedOutputsOp extends TcbOp {
         if (elId === null) {
           elId = this.scope.resolve(this.element);
         }
+        const propertyAccess = ts.createPropertyAccess(elId, 'addEventListener');
+        addParseSpanInfo(propertyAccess, output.keySpan);
         const call = ts.createCall(
-            /* expression */ ts.createPropertyAccess(elId, 'addEventListener'),
+            /* expression */ propertyAccess,
             /* typeArguments */ undefined,
             /* arguments */[ts.createStringLiteral(output.name), handler]);
         addParseSpanInfo(call, output.sourceSpan);