fix #1332: ignore tsconfig.json if target is set

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Changelog
 
+## Unreleased
+
+* Only respect `target` in `tsconfig.json` when esbuild's target is not configured ([#1332](https://github.com/evanw/esbuild/issues/1332))
+
+    In version 0.12.4, esbuild began respecting the `target` setting in `tsconfig.json`. However, sometimes `tsconfig.json` contains target values that should not be used. With this release, esbuild will now only use the `target` value in `tsconfig.json` as the language level when esbuild's `target` setting is not configured. If esbuild's `target` setting is configured then the `target` value in `tsconfig.json` is now ignored.
+
 ## 0.12.5
 
 * Add support for lowering tagged template literals to ES5 ([#297](https://github.com/evanw/esbuild/issues/297))

Makefile

@@ -478,9 +478,8 @@ demo/esprima: | github/esprima
 	cd demo/esprima && npm ci
 
 test-esprima: esbuild | demo/esprima
-	echo {} > demo/esprima/ts.json # Avoid "target: ES5" in "tsconfig.json"
-	cd demo/esprima && ../../esbuild --bundle src/esprima.ts --outfile=dist/esprima.js --target=es6 --platform=node --tsconfig=ts.json && npm run all-tests
-	cd demo/esprima && ../../esbuild --bundle src/esprima.ts --outfile=dist/esprima.js --target=es6 --platform=node --tsconfig=ts.json --minify && npm run all-tests
+	cd demo/esprima && ../../esbuild --bundle src/esprima.ts --outfile=dist/esprima.js --target=es6 --platform=node && npm run all-tests
+	cd demo/esprima && ../../esbuild --bundle src/esprima.ts --outfile=dist/esprima.js --target=es6 --platform=node --minify && npm run all-tests
 
 ################################################################################
 # This runs terser's test suite through esbuild

internal/bundler/bundler_tsconfig_test.go

@@ -1147,8 +1147,9 @@ func TestTsconfigTarget(t *testing.T) {
 		},
 		entryPaths: []string{"/Users/user/project/src/entry.ts"},
 		options: config.Options{
-			Mode:          config.ModeBundle,
-			AbsOutputFile: "/Users/user/project/out.js",
+			Mode:                 config.ModeBundle,
+			AbsOutputFile:        "/Users/user/project/out.js",
+			IsTargetUnconfigured: true,
 		},
 		expectedScanLog: `Users/user/project/src/es4/tsconfig.json: warning: Unrecognized target environment "ES4"
 `,
@@ -1169,16 +1170,37 @@ func TestTsconfigTargetError(t *testing.T) {
 		},
 		entryPaths: []string{"/Users/user/project/src/entry.ts"},
 		options: config.Options{
-			Mode:              config.ModeBundle,
-			AbsOutputFile:     "/Users/user/project/out.js",
-			OriginalTargetEnv: "\"esnext\"", // This should not be reported as the cause of the error
+			Mode:                 config.ModeBundle,
+			AbsOutputFile:        "/Users/user/project/out.js",
+			IsTargetUnconfigured: true,
 		},
 		expectedScanLog: `Users/user/project/src/entry.ts: error: Big integer literals are not available in the configured target environment ("ES2019")
 Users/user/project/src/tsconfig.json: note: The target environment was set to "ES2019" here
 `,
 	})
 }
 
+func TestTsconfigTargetIgnored(t *testing.T) {
+	tsconfig_suite.expectBundled(t, bundled{
+		files: map[string]string{
+			"/Users/user/project/src/entry.ts": `
+				x = 123n
+			`,
+			"/Users/user/project/src/tsconfig.json": `{
+				"compilerOptions": {
+					"target": "ES2019"
+				}
+			}`,
+		},
+		entryPaths: []string{"/Users/user/project/src/entry.ts"},
+		options: config.Options{
+			Mode:                 config.ModeBundle,
+			AbsOutputFile:        "/Users/user/project/out.js",
+			IsTargetUnconfigured: false,
+		},
+	})
+}
+
 func TestTsconfigUseDefineForClassFieldsES2020(t *testing.T) {
 	tsconfig_suite.expectBundled(t, bundled{
 		files: map[string]string{

internal/bundler/snapshots/snapshots_tsconfig.txt

@@ -361,6 +361,12 @@ try {
 }
 x3?.y();
 
+================================================================================
+TestTsconfigTargetIgnored
+---------- /Users/user/project/out.js ----------
+// Users/user/project/src/entry.ts
+x = 123n;
+
 ================================================================================
 TestTsconfigUseDefineForClassFieldsES2020
 ---------- /Users/user/project/out.js ----------

internal/config/config.go

@@ -12,8 +12,6 @@ import (
 	"github.com/evanw/esbuild/internal/logger"
 )
 
-type LanguageTarget int8
-
 type JSXOptions struct {
 	Factory  JSXExpr
 	Fragment JSXExpr
@@ -224,6 +222,7 @@ type Options struct {
 	JSX      JSXOptions
 	Platform Platform
 
+	IsTargetUnconfigured   bool // If true, TypeScript's "target" setting is respected
 	UnsupportedJSFeatures  compat.JSFeature
 	UnsupportedCSSFeatures compat.CSSFeature
 	TSTarget               *TSTarget

internal/js_parser/js_parser.go

@@ -327,6 +327,7 @@ type optionsThatSupportStructuralEquality struct {
 	platform                config.Platform
 	outputFormat            config.Format
 	moduleType              config.ModuleType
+	isTargetUnconfigured    bool
 	asciiOnly               bool
 	keepNames               bool
 	mangleSyntax            bool
@@ -351,6 +352,7 @@ func OptionsFromConfig(options *config.Options) Options {
 			platform:                options.Platform,
 			outputFormat:            options.OutputFormat,
 			moduleType:              options.ModuleType,
+			isTargetUnconfigured:    options.IsTargetUnconfigured,
 			asciiOnly:               options.ASCIIOnly,
 			keepNames:               options.KeepNames,
 			mangleSyntax:            options.MangleSyntax,
@@ -13650,8 +13652,10 @@ func Parse(log logger.Log, source logger.Source, options Options) (result js_ast
 		}
 	}
 
-	// Include unsupported JavaScript features from the TypeScript "target" setting
-	if options.tsTarget != nil {
+	// If there is no top-level esbuild "target" setting, include unsupported
+	// JavaScript features from the TypeScript "target" setting. Otherwise the
+	// TypeScript "target" setting is ignored.
+	if options.isTargetUnconfigured && options.tsTarget != nil {
 		options.unsupportedJSFeatures |= options.tsTarget.UnsupportedJSFeatures
 	}
 

pkg/api/api.go

@@ -115,7 +115,8 @@ const (
 type Target uint8
 
 const (
-	ESNext Target = iota
+	DefaultTarget Target = iota
+	ESNext
 	ES5
 	ES2015
 	ES2016

pkg/api/api_impl.go

@@ -267,7 +267,11 @@ func validateEngine(value EngineName) compat.Engine {
 
 var versionRegex = regexp.MustCompile(`^([0-9]+)(?:\.([0-9]+))?(?:\.([0-9]+))?$`)
 
-func validateFeatures(log logger.Log, target Target, engines []Engine) (compat.JSFeature, compat.CSSFeature, string) {
+func validateFeatures(log logger.Log, target Target, engines []Engine) (bool, compat.JSFeature, compat.CSSFeature, string) {
+	if target == DefaultTarget && len(engines) == 0 {
+		return true, 0, 0, ""
+	}
+
 	constraints := make(map[compat.Engine][]int)
 	targets := make([]string, 0, 1+len(engines))
 
@@ -286,7 +290,7 @@ func validateFeatures(log logger.Log, target Target, engines []Engine) (compat.J
 		constraints[compat.ES] = []int{2019}
 	case ES2020:
 		constraints[compat.ES] = []int{2020}
-	case ESNext:
+	case ESNext, DefaultTarget:
 	default:
 		panic("Invalid target")
 	}
@@ -340,7 +344,7 @@ func validateFeatures(log logger.Log, target Target, engines []Engine) (compat.J
 	sort.Strings(targets)
 	targetEnv := strings.Join(targets, ", ")
 
-	return compat.UnsupportedJSFeatures(constraints), compat.UnsupportedCSSFeatures(constraints), targetEnv
+	return false, compat.UnsupportedJSFeatures(constraints), compat.UnsupportedCSSFeatures(constraints), targetEnv
 }
 
 func validateGlobalName(log logger.Log, text string) []string {
@@ -788,13 +792,14 @@ func rebuildImpl(
 		// This should already have been checked above
 		panic(err.Error())
 	}
-	jsFeatures, cssFeatures, targetEnv := validateFeatures(log, buildOpts.Target, buildOpts.Engines)
+	isTargetUnconfigured, jsFeatures, cssFeatures, targetEnv := validateFeatures(log, buildOpts.Target, buildOpts.Engines)
 	outJS, outCSS := validateOutputExtensions(log, buildOpts.OutExtensions)
 	bannerJS, bannerCSS := validateBannerOrFooter(log, "banner", buildOpts.Banner)
 	footerJS, footerCSS := validateBannerOrFooter(log, "footer", buildOpts.Footer)
 	minify := buildOpts.MinifyWhitespace && buildOpts.MinifyIdentifiers && buildOpts.MinifySyntax
 	defines, injectedDefines := validateDefines(log, buildOpts.Define, buildOpts.Pure, buildOpts.Platform, minify)
 	options := config.Options{
+		IsTargetUnconfigured:   isTargetUnconfigured,
 		UnsupportedJSFeatures:  jsFeatures,
 		UnsupportedCSSFeatures: cssFeatures,
 		OriginalTargetEnv:      targetEnv,
@@ -1276,9 +1281,10 @@ func transformImpl(input string, transformOpts TransformOptions) TransformResult
 	}
 
 	// Convert and validate the transformOpts
-	jsFeatures, cssFeatures, targetEnv := validateFeatures(log, transformOpts.Target, transformOpts.Engines)
+	isTargetUnconfigured, jsFeatures, cssFeatures, targetEnv := validateFeatures(log, transformOpts.Target, transformOpts.Engines)
 	defines, injectedDefines := validateDefines(log, transformOpts.Define, transformOpts.Pure, PlatformNeutral, false /* minify */)
 	options := config.Options{
+		IsTargetUnconfigured:    isTargetUnconfigured,
 		UnsupportedJSFeatures:   jsFeatures,
 		UnsupportedCSSFeatures:  cssFeatures,
 		OriginalTargetEnv:       targetEnv,