Attempt to handle possibly-empty-looking loops better

... but it's failing and I'm not sure why
jbt · May 13, 2017 · 629c560 · 629c560
1 parent e1c2b2a
commit 629c560
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Showing 4 changed files with 42 additions and 6 deletions.
diff --git a/src/program/types/DoWhileStatement.js b/src/program/types/DoWhileStatement.js
@@ -3,7 +3,7 @@ import Node from '../Node.js';
 export default class DoWhileStatement extends Node {
 	minify ( code ) {
 		// special case
-		if ( this.body.body.length === 0 || this.body.body[0].type === 'EmptyStatement' ) {
+		if ( this.body.body.every( node => node.type === 'EmptyStatement' ) ) {
 			code.overwrite( this.start + 2, this.test.start, ';while(' );
 		}
 

diff --git a/src/program/types/WhileStatement.js b/src/program/types/WhileStatement.js
@@ -15,7 +15,7 @@ export default class WhileStatement extends Node {
 		}
 
 		// special case — empty body
-		if ( this.body.body.length === 0 || this.body.body[0].type === 'EmptyStatement' ) {
+		if ( this.body.body.every( node => node.type === 'EmptyStatement' ) ) {
 			code.appendLeft( this.body.start, ';' );
 			code.remove( this.body.start, this.body.end );
 		}

diff --git a/src/program/types/shared/LoopStatement.js b/src/program/types/shared/LoopStatement.js
@@ -10,7 +10,7 @@ export default class LoopStatement extends Node {
 
 	minify ( code ) {
 		// special case — empty body
-		if ( this.body.body.length === 0 || this.body.body[0].type === 'EmptyStatement' ) {
+		if ( this.body.body.every( node => node.type === 'EmptyStatement' ) ) {
 			code.appendLeft( this.body.start, ';' );
 			code.remove( this.body.start, this.body.end );
 		}

diff --git a/test/samples/loops.js b/test/samples/loops.js
@@ -157,6 +157,42 @@ module.exports = [
 		output: `for(;;x());`
 	},
 
+	{
+		description: 'handles essentially-empty while loop body',
+		input: `while ( x() ) { ; ; }`,
+		output: `while(x());`
+	},
+
+	{
+		description: 'handles essentially-empty do-while loop body',
+		input: `do { ; ; } while ( x() );`,
+		output: `do;while(x())`
+	},
+
+	{
+		description: 'handles essentially-empty for loop body',
+		input: `for ( ; ; x() ) { ; ; }`,
+		output: `for(;;x());`
+	},
+
+	{
+		description: 'handles non-empty while loop body starting with empty statement',
+		input: `while ( x() ) { ; a(); }`,
+		output: `while(x()) a();`
+	},
+
+	{
+		description: 'handles non-empty do-while loop body starting with empty statement',
+		input: `do { ; a(); } while ( x() );`,
+		output: `do a();while(x())`
+	},
+
+	{
+		description: 'handles non-empty for loop body starting with empty statement',
+		input: `for ( ; ; x() ) { ; a(); }`,
+		output: `for(;;x()) a();`
+	},
+
 	{
 		description: 'handles duplicate let declarations in for-of loop head',
 		input: `
@@ -179,9 +215,9 @@ module.exports = [
 				}
 			})();`,
 		output: `!(()=>{let a=0;for(;;)f(a)})()`
-  },
-  
-  {
+	},
+
+	{
 		description: 'preserves semi-colon for body-less while loop at end of body',
 		input: `
 			function f() {