close #3026: remove unneeded spaces after numbers

CHANGELOG.md

@@ -42,6 +42,21 @@
 
     Note that you need to specify both `--format=cjs` and `--platform=node` to get these node-specific annotations.
 
+* Avoid printing an unnecessary space in between a number and a `.` ([#3026](https://github.com/evanw/esbuild/pull/3026))
+
+    JavaScript typically requires a space in between a number token and a `.` token to avoid the `.` being interpreted as a decimal point instead of a member expression. However, this space is not required if the number token itself contains a decimal point, an exponent, or uses a base other than 10. This release of esbuild now avoids printing the unnecessary space in these cases:
+
+    ```js
+    // Original input
+    foo(1000 .x, 0 .x, 0.1 .x, 0.0001 .x, 0xFFFF_0000_FFFF_0000 .x)
+
+    // Old output (with --minify)
+    foo(1e3 .x,0 .x,.1 .x,1e-4 .x,0xffff0000ffff0000 .x);
+
+    // New output (with --minify)
+    foo(1e3.x,0 .x,.1.x,1e-4.x,0xffff0000ffff0000.x);
+    ```
+
 ## 0.17.14
 
 * Allow the TypeScript 5.0 `const` modifier in object type declarations ([#3021](https://github.com/evanw/esbuild/issues/3021))

internal/js_printer/js_printer.go

@@ -350,7 +350,7 @@ type printer struct {
 	forOfInitStart     int
 
 	prevOpEnd            int
-	prevNumEnd           int
+	needSpaceBeforeDot   int
 	prevRegExpEnd        int
 	noLeadingNewlineHere int
 	intToBytesBuffer     [64]byte
@@ -515,9 +515,6 @@ func (p *printer) printNumber(value float64, level js_ast.L) {
 		if !math.Signbit(value) {
 			p.printSpaceBeforeIdentifier()
 			p.printNonNegativeFloat(absValue)
-
-			// Remember the end of the latest number
-			p.prevNumEnd = len(p.js)
 		} else if level >= js_ast.LPrefix {
 			// Expressions such as "(-1).toString" need to wrap negative numbers.
 			// Instead of testing for "value < 0" we test for "signbit(value)" and
@@ -530,9 +527,6 @@ func (p *printer) printNumber(value float64, level js_ast.L) {
 			p.printSpaceBeforeOperator(js_ast.UnOpNeg)
 			p.print("-")
 			p.printNonNegativeFloat(absValue)
-
-			// Remember the end of the latest number
-			p.prevNumEnd = len(p.js)
 		}
 	}
 }
@@ -1415,7 +1409,6 @@ func (p *printer) printUndefined(loc logger.Loc, level js_ast.L) {
 		p.printSpaceBeforeIdentifier()
 		p.addSourceMapping(loc)
 		p.print("void 0")
-		p.prevNumEnd = len(p.js)
 	}
 }
 
@@ -2295,7 +2288,7 @@ func (p *printer) printExpr(expr js_ast.Expr, level js_ast.L, flags printExprFla
 		}
 		p.printExpr(e.Target, js_ast.LPostfix, flags&(forbidCall|hasNonOptionalChainParent))
 		if p.canPrintIdentifier(e.Name) {
-			if e.OptionalChain != js_ast.OptionalChainStart && p.prevNumEnd == len(p.js) {
+			if e.OptionalChain != js_ast.OptionalChainStart && p.needSpaceBeforeDot == len(p.js) {
 				// "1.toString" is a syntax error, so print "1 .toString" instead
 				p.print(" ")
 			}
@@ -3169,6 +3162,9 @@ func (p *printer) printNonNegativeFloat(absValue float64) {
 	if absValue < 1000 {
 		if asInt := int64(absValue); absValue == float64(asInt) {
 			p.printBytes(p.smallIntToBytes(int(asInt)))
+
+			// Integers always need a space before "." to avoid making a decimal point
+			p.needSpaceBeforeDot = len(p.js)
 			return
 		}
 	}
@@ -3290,6 +3286,11 @@ func (p *printer) printNonNegativeFloat(absValue float64) {
 	}
 
 	p.printBytes(result)
+
+	// We'll need a space before "." if it could be parsed as a decimal point
+	if !bytes.ContainsAny(result, ".ex") {
+		p.needSpaceBeforeDot = len(p.js)
+	}
 }
 
 func (p *printer) printDeclStmt(isExport bool, keyword string, decls []js_ast.Decl) {
@@ -4523,7 +4524,7 @@ func Print(tree js_ast.AST, symbols js_ast.SymbolMap, r renamer.Renamer, options
 		forOfInitStart:     -1,
 
 		prevOpEnd:            -1,
-		prevNumEnd:           -1,
+		needSpaceBeforeDot:   -1,
 		prevRegExpEnd:        -1,
 		noLeadingNewlineHere: -1,
 		builder:              sourcemap.MakeChunkBuilder(options.InputSourceMap, options.LineOffsetTables, options.ASCIIOnly),

internal/js_printer/js_printer_test.go

@@ -279,6 +279,18 @@ func TestNumber(t *testing.T) {
 	expectPrintedMinify(t, "x = 0xFFFF_FFFF_FFFF_F000", "x=0xfffffffffffff000;")
 	expectPrintedMinify(t, "x = 0xFFFF_FFFF_FFFF_F800", "x=1844674407370955e4;")
 	expectPrintedMinify(t, "x = 0xFFFF_FFFF_FFFF_FFFF", "x=18446744073709552e3;")
+
+	// Check printing a space in between a number and a subsequent "."
+	expectPrintedMinify(t, "x = 0.0001 .y", "x=1e-4.y;")
+	expectPrintedMinify(t, "x = 0.001 .y", "x=.001.y;")
+	expectPrintedMinify(t, "x = 0.01 .y", "x=.01.y;")
+	expectPrintedMinify(t, "x = 0.1 .y", "x=.1.y;")
+	expectPrintedMinify(t, "x = 0 .y", "x=0 .y;")
+	expectPrintedMinify(t, "x = 10 .y", "x=10 .y;")
+	expectPrintedMinify(t, "x = 100 .y", "x=100 .y;")
+	expectPrintedMinify(t, "x = 1000 .y", "x=1e3.y;")
+	expectPrintedMinify(t, "x = 12345 .y", "x=12345 .y;")
+	expectPrintedMinify(t, "x = 0xFFFF_0000_FFFF_0000 .y", "x=0xffff0000ffff0000.y;")
 }
 
 func TestArray(t *testing.T) {