Move adding of implicit return values to the block statement and

tree-shake arrow functions with block statement bodies.
rollup · Nov 8, 2017 · bd911aa · bd911aa
1 parent 7aa94bc
commit bd911aa
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Showing 10 changed files with 68 additions and 27 deletions.
diff --git a/src/ast/nodes/ArrowFunctionExpression.js b/src/ast/nodes/ArrowFunctionExpression.js
@@ -1,8 +1,14 @@
 import Node from '../Node';
-import Scope from '../scopes/Scope.js';
-import { UNKNOWN_ASSIGNMENT } from '../values';
+import Scope from '../scopes/Scope';
+import ReturnValueScope from '../scopes/ReturnValueScope';
 
 export default class ArrowFunctionExpression extends Node {
+	bindNode () {
+		this.body.bindImplicitReturnExpressionToScope
+			? this.body.bindImplicitReturnExpressionToScope()
+			: this.scope.addReturnExpression( this.body );
+	}
+
 	hasEffects () {
 		return this.included;
 	}
@@ -33,13 +39,10 @@ export default class ArrowFunctionExpression extends Node {
 	}
 
 	initialiseScope ( parentScope ) {
-		this.scope = new Scope( { parent: parentScope } );
+		this.scope = new ReturnValueScope( { parent: parentScope } );
 	}
 
 	someReturnExpressionAtPath ( path, callOptions, predicateFunction ) {
-		if ( this.body.type !== 'BlockStatement' ) {
-			return predicateFunction( path, this.body );
-		}
-		return predicateFunction( path, UNKNOWN_ASSIGNMENT );
+		return this.scope.someReturnExpressionAtPath( path, callOptions, predicateFunction );
 	}
 }
diff --git a/src/ast/nodes/BlockStatement.js b/src/ast/nodes/BlockStatement.js
@@ -1,7 +1,15 @@
 import Statement from './shared/Statement.js';
 import BlockScope from '../scopes/BlockScope';
+import UndefinedIdentifier from './shared/UndefinedIdentifier';
 
 export default class BlockStatement extends Statement {
+	bindImplicitReturnExpressionToScope () {
+		const lastStatement = this.body[ this.body.length - 1 ];
+		if ( !lastStatement || lastStatement.type !== 'ReturnStatement' ) {
+			this.scope.addReturnExpression( new UndefinedIdentifier() );
+		}
+	}
+
 	hasEffects ( options ) {
 		// Empty block statements do not have effects even though they may be included as e.g. function body
 		return this.body.some( child => child.hasEffects( options ) );

diff --git a/src/ast/nodes/shared/FunctionNode.js b/src/ast/nodes/shared/FunctionNode.js
@@ -1,12 +1,12 @@
 import Node from '../../Node.js';
 import FunctionScope from '../../scopes/FunctionScope';
 import VirtualObjectExpression from './VirtualObjectExpression';
-import UndefinedIdentifier from './UndefinedIdentifier';
 import { UNKNOWN_ASSIGNMENT } from '../../values';
 
 export default class FunctionNode extends Node {
 	bindNode () {
 		this.thisVariable = this.scope.findVariable( 'this' );
+		this.body.bindImplicitReturnExpressionToScope();
 	}
 
 	hasEffects ( options ) {
@@ -45,10 +45,6 @@ export default class FunctionNode extends Node {
 
 	initialiseNode () {
 		this.prototypeObject = new VirtualObjectExpression();
-		const lastBodyStatement = this.body.body[ this.body.body.length - 1 ];
-		if ( !lastBodyStatement || lastBodyStatement.type !== 'ReturnStatement' ) {
-			this.scope.addReturnExpression( new UndefinedIdentifier() );
-		}
 	}
 
 	initialiseScope ( parentScope ) {

diff --git a/test/form/samples/arrow-function-return-values/_config.js b/test/form/samples/arrow-function-return-values/_config.js
@@ -1,3 +1,3 @@
 module.exports = {
-	description: 'forwards return values of body-less arrow functions'
+	description: 'forwards return values of arrow functions'
 };
diff --git a/test/form/samples/arrow-function-return-values/_expected/amd.js b/test/form/samples/arrow-function-return-values/_expected/amd.js
@@ -4,7 +4,12 @@ define(function () { 'use strict';
 
 	(() => () => () => console.log( 'effect' ))()()();
 
-	const bar = () => () => console.log('effect');
-	bar()();
+	const retained1 = () => () => console.log( 'effect' );
+	retained1()();
+
+	const retained2 = () => {
+		return () => console.log( 'effect' );
+	};
+	retained2()();
 
 });
diff --git a/test/form/samples/arrow-function-return-values/_expected/cjs.js b/test/form/samples/arrow-function-return-values/_expected/cjs.js
@@ -4,5 +4,10 @@
 
 (() => () => () => console.log( 'effect' ))()()();
 
-const bar = () => () => console.log('effect');
-bar()();
+const retained1 = () => () => console.log( 'effect' );
+retained1()();
+
+const retained2 = () => {
+	return () => console.log( 'effect' );
+};
+retained2()();
diff --git a/test/form/samples/arrow-function-return-values/_expected/es.js b/test/form/samples/arrow-function-return-values/_expected/es.js
@@ -2,5 +2,10 @@
 
 (() => () => () => console.log( 'effect' ))()()();
 
-const bar = () => () => console.log('effect');
-bar()();
+const retained1 = () => () => console.log( 'effect' );
+retained1()();
+
+const retained2 = () => {
+	return () => console.log( 'effect' );
+};
+retained2()();
diff --git a/test/form/samples/arrow-function-return-values/_expected/iife.js b/test/form/samples/arrow-function-return-values/_expected/iife.js
@@ -5,7 +5,12 @@
 
 	(() => () => () => console.log( 'effect' ))()()();
 
-	const bar = () => () => console.log('effect');
-	bar()();
+	const retained1 = () => () => console.log( 'effect' );
+	retained1()();
+
+	const retained2 = () => {
+		return () => console.log( 'effect' );
+	};
+	retained2()();
 
 }());
diff --git a/test/form/samples/arrow-function-return-values/_expected/umd.js b/test/form/samples/arrow-function-return-values/_expected/umd.js
@@ -8,7 +8,12 @@
 
 	(() => () => () => console.log( 'effect' ))()()();
 
-	const bar = () => () => console.log('effect');
-	bar()();
+	const retained1 = () => () => console.log( 'effect' );
+	retained1()();
+
+	const retained2 = () => {
+		return () => console.log( 'effect' );
+	};
+	retained2()();
 
 })));
diff --git a/test/form/samples/arrow-function-return-values/main.js b/test/form/samples/arrow-function-return-values/main.js
@@ -4,7 +4,16 @@
 (() => () => () => {})()()();
 (() => () => () => console.log( 'effect' ))()()();
 
-const foo = () => () => {};
-foo()();
-const bar = () => () => console.log('effect');
-bar()();
+const removed1 = () => () => {};
+removed1()();
+const retained1 = () => () => console.log( 'effect' );
+retained1()();
+
+const removed2 = () => {
+	return () => {};
+};
+removed2()();
+const retained2 = () => {
+	return () => console.log( 'effect' );
+};
+retained2()();