Refine code formatting

rollup · Sep 18, 2021 · 028d45e · 028d45e
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diff --git a/docs/999-big-list-of-options.md b/docs/999-big-list-of-options.md
@@ -473,7 +473,7 @@ Whether to use arrow functions for auto-generated code snippets. Note that in ce
 
 **output.generatedCode.constBindings**<br> Type: `boolean`<br> CLI: `--generatedCode.constBindings`/`--no-generatedCode.constBindings`<br> Default: `false`
 
-This will use `const` instead of `var` in certain places and helper functions. Depending on the engine, this can provide [marginally better performance](https://benediktmeurer.de/2017/06/29/javascript-optimization-patterns-part2) in optimized machine code. It will also allow Rollup to generate more efficient helpers due to block scoping.
+This will use `const` instead of `var` in certain places and helper functions. This will allow Rollup to generate more efficient helpers due to block scoping.
 
 ```js
 // input
@@ -555,7 +555,7 @@ export default {
 
 **output.generatedCode.reservedNamesAsProps**<br> Type: `boolean`<br> CLI: `--generatedCode.reservedNamesAsProps`/`--no-generatedCode.reservedNamesAsProps`<br> Default: `false`
 
-Determine whether reserved words like "default" can be used as prop names without using quotes.
+Determine whether reserved words like "default" can be used as prop names without using quotes. This will make the syntax of the generated code ES3 compliant. Note however that for full ES3 compliance, you may also need to polyfill some builtin functions like `Object.keys` or `Array.prototype.forEach`.
 
 ```javascript
 // input

diff --git a/src/ast/nodes/ImportExpression.ts b/src/ast/nodes/ImportExpression.ts
@@ -50,11 +50,10 @@ export default class ImportExpression extends NodeBase {
 			const {
 				snippets: { getDirectReturnFunction, getPropertyAccess }
 			} = options;
-			const { left, right } = getDirectReturnFunction([], {
+			const [left, right] = getDirectReturnFunction([], {
 				functionReturn: true,
-				lineBreakIndent: false,
-				name: null,
-				t: ''
+				lineBreakIndent: null,
+				name: null
 			});
 			code.overwrite(
 				this.start,
@@ -85,11 +84,10 @@ export default class ImportExpression extends NodeBase {
 	): void {
 		code.overwrite(this.source.start, this.source.end, resolution);
 		if (namespaceExportName) {
-			const { left, right } = getDirectReturnFunction(['n'], {
+			const [left, right] = getDirectReturnFunction(['n'], {
 				functionReturn: true,
-				lineBreakIndent: false,
-				name: null,
-				t: ''
+				lineBreakIndent: null,
+				name: null
 			});
 			code.prependLeft(this.end, `.then(${left}n.${namespaceExportName}${right})`);
 		}
@@ -161,11 +159,10 @@ export default class ImportExpression extends NodeBase {
 					left = `/*#__PURE__*/${helper}(${left}`;
 					right += ')';
 				}
-				const { left: functionLeft, right: functionRight } = getDirectReturnFunction([], {
+				const [functionLeft, functionRight] = getDirectReturnFunction([], {
 					functionReturn: true,
-					lineBreakIndent: false,
-					name: null,
-					t: ''
+					lineBreakIndent: null,
+					name: null
 				});
 				left = `Promise.resolve().then(${functionLeft}${left}`;
 				right += `${functionRight})`;
@@ -185,24 +182,19 @@ export default class ImportExpression extends NodeBase {
 				const resolve = compact ? 'c' : 'resolve';
 				const reject = compact ? 'e' : 'reject';
 				const helper = getInteropHelper(resolution, exportMode, interop);
-				const { left: resolveLeft, right: resolveRight } = getDirectReturnFunction(['m'], {
+				const [resolveLeft, resolveRight] = getDirectReturnFunction(['m'], {
 					functionReturn: false,
-					lineBreakIndent: false,
-					name: null,
-					t: ''
+					lineBreakIndent: null,
+					name: null
 				});
 				const resolveNamespace = helper
 					? `${resolveLeft}${resolve}(/*#__PURE__*/${helper}(m))${resolveRight}`
 					: resolve;
-				const { left: handlerLeft, right: handlerRight } = getDirectReturnFunction(
-					[resolve, reject],
-					{
-						functionReturn: false,
-						lineBreakIndent: false,
-						name: null,
-						t: ''
-					}
-				);
+				const [handlerLeft, handlerRight] = getDirectReturnFunction([resolve, reject], {
+					functionReturn: false,
+					lineBreakIndent: null,
+					name: null
+				});
 				let left = `new Promise(${handlerLeft}require([`;
 				let right = `],${_}${resolveNamespace},${_}${reject})${handlerRight})`;
 				if (!arrowFunctions && hasDynamicTarget) {

diff --git a/src/ast/variables/NamespaceVariable.ts b/src/ast/variables/NamespaceVariable.ts
@@ -83,7 +83,7 @@ export default class NamespaceVariable extends Variable {
 
 		members.unshift([null, `__proto__:${_}null`]);
 
-		let output = getObject(members, { lineBreakIndent: t });
+		let output = getObject(members, { lineBreakIndent: { base: '', t } });
 		if (this.mergedNamespaces.length > 0) {
 			const assignmentArgs = this.mergedNamespaces.map(variable =>
 				variable.getName(getPropertyAccess)

diff --git a/src/finalisers/shared/getExportBlock.ts b/src/finalisers/shared/getExportBlock.ts
@@ -56,11 +56,10 @@ export function getExportBlock(
 					);
 					if (exportBlock) exportBlock += n;
 					if (specifier.imported !== '*' && specifier.needsLiveBinding) {
-						const { left, right } = getDirectReturnFunction([], {
+						const [left, right] = getDirectReturnFunction([], {
 							functionReturn: true,
-							lineBreakIndent: false,
-							name: null,
-							t: ''
+							lineBreakIndent: null,
+							name: null
 						});
 						exportBlock +=
 							`Object.defineProperty(exports,${_}'${specifier.reexported}',${_}{${n}` +
@@ -227,11 +226,10 @@ const getDefineProperty = (
 	{ _, getDirectReturnFunction, n }: GenerateCodeSnippets
 ) => {
 	if (needsLiveBinding) {
-		const { left, right } = getDirectReturnFunction([], {
+		const [left, right] = getDirectReturnFunction([], {
 			functionReturn: true,
-			lineBreakIndent: false,
-			name: null,
-			t: ''
+			lineBreakIndent: null,
+			name: null
 		});
 		return (
 			`Object.defineProperty(exports,${_}k,${_}{${n}` +

diff --git a/src/finalisers/system.ts b/src/finalisers/system.ts
@@ -132,7 +132,7 @@ function analyzeDependencies(
 				}
 			}
 			if (reexportedNames.length > 1 || hasStarReexport) {
-				const exportMapping = getObject(reexportedNames, { lineBreakIndent: false });
+				const exportMapping = getObject(reexportedNames, { lineBreakIndent: null });
 				if (hasStarReexport) {
 					if (!starExcludes) {
 						starExcludes = getStarExcludes({ dependencies, exports });
@@ -178,7 +178,7 @@ const getStarExcludesBlock = (
 	starExcludes
 		? `${n}${t}${cnst} _starExcludes${_}=${_}${getObject(
 				[...starExcludes].map(prop => [prop, '1']),
-				{ lineBreakIndent: false }
+				{ lineBreakIndent: { base: t, t } }
 		  )};`
 		: '';
 

diff --git a/src/utils/generateCodeSnippets.ts b/src/utils/generateCodeSnippets.ts
@@ -10,11 +10,10 @@ export interface GenerateCodeSnippets {
 		params: string[],
 		options: {
 			functionReturn: boolean;
-			lineBreakIndent: string | false;
+			lineBreakIndent: { base: string; t: string } | null;
 			name: string | null;
-			t: string;
 		}
-	): { left: string; right: string };
+	): [left: string, right: string];
 	getDirectReturnIifeLeft(
 		params: string[],
 		returned: string,
@@ -28,10 +27,9 @@ export interface GenerateCodeSnippets {
 		params: string[],
 		options: { isAsync: boolean; name: string | null }
 	): string;
-	// TODO Lukas adjust line-break handling with functions, change in System wrapper
 	getObject(
 		fields: [key: string | null, value: string][],
-		options: { lineBreakIndent: string | false }
+		options: { lineBreakIndent: { base: string; t: string } | null }
 	): string;
 	getPropertyAccess(name: string): string;
 }
@@ -60,22 +58,24 @@ export function getGenerateCodeSnippets({
 
 	const getDirectReturnFunction: GenerateCodeSnippets['getDirectReturnFunction'] = (
 		params,
-		{ functionReturn, t, lineBreakIndent, name }
-	) => ({
-		left: `${getFunctionIntro(params, {
+		{ functionReturn, lineBreakIndent, name }
+	) => [
+		`${getFunctionIntro(params, {
 			isAsync: false,
 			name
 		})}${
 			arrowFunctions
 				? lineBreakIndent
-					? `${n}${lineBreakIndent}${t}`
+					? `${n}${lineBreakIndent.base}${lineBreakIndent.t}`
 					: ''
-				: `{${lineBreakIndent ? `${n}${lineBreakIndent}${t}` : _}${functionReturn ? 'return ' : ''}`
+				: `{${lineBreakIndent ? `${n}${lineBreakIndent.base}${lineBreakIndent.t}` : _}${
+						functionReturn ? 'return ' : ''
+				  }`
 		}`,
-		right: arrowFunctions
-			? `${name ? ';' : ''}${lineBreakIndent ? `${n}${lineBreakIndent}` : ''}`
-			: `${s}${lineBreakIndent ? `${n}${lineBreakIndent}` : _}}`
-	});
+		arrowFunctions
+			? `${name ? ';' : ''}${lineBreakIndent ? `${n}${lineBreakIndent.base}` : ''}`
+			: `${s}${lineBreakIndent ? `${n}${lineBreakIndent.base}` : _}}`
+	];
 
 	const isValidPropName = reservedNamesAsProps
 		? (name: string): boolean => validPropName.test(name)
@@ -90,11 +90,10 @@ export function getGenerateCodeSnippets({
 			returned,
 			{ needsArrowReturnParens, needsWrappedFunction }
 		) => {
-			const { left, right } = getDirectReturnFunction(params, {
+			const [left, right] = getDirectReturnFunction(params, {
 				functionReturn: true,
-				lineBreakIndent: false,
-				name: null,
-				t: ''
+				lineBreakIndent: null,
+				name: null
 			});
 			return `${wrapIfNeeded(
 				`${left}${wrapIfNeeded(returned, arrowFunctions && needsArrowReturnParens)}${right}`,
@@ -104,7 +103,7 @@ export function getGenerateCodeSnippets({
 		getFunctionIntro,
 		getNonArrowFunctionIntro,
 		getObject(fields, { lineBreakIndent }) {
-			const prefix = lineBreakIndent === false ? _ : `${n}${lineBreakIndent}`;
+			const prefix = lineBreakIndent ? `${n}${lineBreakIndent.base}${lineBreakIndent.t}` : _;
 			return `{${fields
 				.map(([key, value]) => {
 					if (key === null) return `${prefix}${value}`;
@@ -113,7 +112,9 @@ export function getGenerateCodeSnippets({
 						? prefix + key
 						: `${prefix}${needsQuotes ? `'${key}'` : key}:${_}${value}`;
 				})
-				.join(`,`)}${fields.length === 0 ? '' : lineBreakIndent === false ? _ : n}}`;
+				.join(`,`)}${
+				fields.length === 0 ? '' : lineBreakIndent ? `${n}${lineBreakIndent.base}` : _
+			}}`;
 		},
 		getPropertyAccess: (name: string): string =>
 			isValidPropName(name) ? `.${name}` : `[${JSON.stringify(name)}]`,

diff --git a/src/utils/interopHelpers.ts b/src/utils/interopHelpers.ts
@@ -77,11 +77,10 @@ const HELPER_GENERATORS: {
 } = {
 	[INTEROP_DEFAULT_LEGACY_VARIABLE](_t, snippets, liveBindings) {
 		const { _, getDirectReturnFunction, n } = snippets;
-		const { left, right } = getDirectReturnFunction(['e'], {
+		const [left, right] = getDirectReturnFunction(['e'], {
 			functionReturn: true,
-			lineBreakIndent: false,
-			name: INTEROP_DEFAULT_LEGACY_VARIABLE,
-			t: ''
+			lineBreakIndent: null,
+			name: INTEROP_DEFAULT_LEGACY_VARIABLE
 		});
 		return (
 			`${left}e${_}&&${_}typeof e${_}===${_}'object'${_}&&${_}'default'${_}in e${_}?${_}` +
@@ -92,11 +91,10 @@ const HELPER_GENERATORS: {
 	},
 	[INTEROP_DEFAULT_VARIABLE](_t, snippets, liveBindings) {
 		const { _, getDirectReturnFunction, n } = snippets;
-		const { left, right } = getDirectReturnFunction(['e'], {
+		const [left, right] = getDirectReturnFunction(['e'], {
 			functionReturn: true,
-			lineBreakIndent: false,
-			name: INTEROP_DEFAULT_VARIABLE,
-			t: ''
+			lineBreakIndent: null,
+			name: INTEROP_DEFAULT_VARIABLE
 		});
 		return (
 			`${left}e${_}&&${_}e.__esModule${_}?${_}` +
@@ -112,11 +110,10 @@ const HELPER_GENERATORS: {
 		freeze: boolean,
 		namespaceToStringTag: boolean
 	) {
-		const { left, right } = getDirectReturnFunction(['e'], {
+		const [left, right] = getDirectReturnFunction(['e'], {
 			functionReturn: true,
-			lineBreakIndent: false,
-			name: INTEROP_NAMESPACE_DEFAULT_ONLY_VARIABLE,
-			t: ''
+			lineBreakIndent: null,
+			name: INTEROP_NAMESPACE_DEFAULT_ONLY_VARIABLE
 		});
 		return `${left}${getFrozen(
 			getObject(
@@ -127,7 +124,7 @@ const HELPER_GENERATORS: {
 						: []),
 					['default', 'e']
 				],
-				{ lineBreakIndent: false }
+				{ lineBreakIndent: null }
 			),
 			freeze
 		)}${right}${n}${n}`;
@@ -150,11 +147,10 @@ const HELPER_GENERATORS: {
 	) {
 		const { _, getDirectReturnFunction, n } = snippets;
 		if (usedHelpers.has(INTEROP_NAMESPACE_DEFAULT_VARIABLE)) {
-			const { left, right } = getDirectReturnFunction(['e'], {
+			const [left, right] = getDirectReturnFunction(['e'], {
 				functionReturn: true,
-				lineBreakIndent: false,
-				name: INTEROP_NAMESPACE_VARIABLE,
-				t: ''
+				lineBreakIndent: null,
+				name: INTEROP_NAMESPACE_VARIABLE
 			});
 			return `${left}e${_}&&${_}e.__esModule${_}?${_}e${_}:${_}${INTEROP_NAMESPACE_DEFAULT_VARIABLE}(e)${right}${n}${n}`;
 		}
@@ -167,7 +163,6 @@ const HELPER_GENERATORS: {
 	},
 	[MERGE_NAMESPACES_VARIABLE](t, snippets, liveBindings, freeze) {
 		const { _, n } = snippets;
-		// TODO Lukas mention improved helpers and used builtins in generatedCode docs
 		return (
 			`function ${MERGE_NAMESPACES_VARIABLE}(n, m)${_}{${n}` +
 			`${t}${loopOverNamespaces(
@@ -191,7 +186,7 @@ const HELPER_GENERATORS: {
 };
 
 const getDefaultLiveBinding = ({ _, getObject }: GenerateCodeSnippets) =>
-	`e${_}:${_}${getObject([['default', 'e']], { lineBreakIndent: false })}`;
+	`e${_}:${_}${getObject([['default', 'e']], { lineBreakIndent: null })}`;
 
 const getDefaultStatic = ({ _, getPropertyAccess }: GenerateCodeSnippets) =>
 	`e${getPropertyAccess('default')}${_}:${_}e`;
@@ -220,7 +215,7 @@ const createNamespaceObject = (
 				: 'Object.create(null)'
 		};${n}` +
 		`${i}if${_}(e)${_}{${n}` +
-		`${i}${t}${loopOverKeys(copyProperty, !liveBindings, true, snippets)}${n}` +
+		`${i}${t}${loopOverKeys(copyProperty, !liveBindings, snippets)}${n}` +
 		`${i}}${n}` +
 		`${i}n${getPropertyAccess('default')}${_}=${_}e;${n}` +
 		`${i}return ${getFrozen('n', freeze)}${s}${n}`
@@ -230,15 +225,14 @@ const createNamespaceObject = (
 const loopOverKeys = (
 	body: string,
 	allowVarLoopVariable: boolean,
-	isStatement: boolean,
 	{ _, cnst, getFunctionIntro, s }: GenerateCodeSnippets
 ) =>
 	cnst !== 'var' || allowVarLoopVariable
-		? wrapBracesIfNeeded(`for${_}(${cnst} k in e)${_}${body}`, !isStatement, _)
+		? `for${_}(${cnst} k in e)${_}${body}`
 		: `Object.keys(e).forEach(${getFunctionIntro(['k'], {
 				isAsync: false,
 				name: null
-		  })}${body})${isStatement ? s : ''}`;
+		  })}${body})${s}`;
 
 const loopOverNamespaces = (
 	body: string,
@@ -253,11 +247,10 @@ const loopOverNamespaces = (
 			`${t}${t}for${_}(${cnst} k in e)${_}${body}${n}${t}}`
 		);
 	}
-	const { left, right } = getDirectReturnFunction(['e'], {
+	const [left, right] = getDirectReturnFunction(['e'], {
 		functionReturn: false,
-		lineBreakIndent: t,
-		name: null,
-		t
+		lineBreakIndent: { base: t, t },
+		name: null
 	});
 	return (
 		`m.forEach(${left}` +
@@ -286,11 +279,10 @@ const copyPropertyLiveBinding = (
 	i: string,
 	{ _, cnst, getDirectReturnFunction, n }: GenerateCodeSnippets
 ) => {
-	const { left, right } = getDirectReturnFunction([], {
+	const [left, right] = getDirectReturnFunction([], {
 		functionReturn: true,
-		lineBreakIndent: false,
-		name: null,
-		t: ''
+		lineBreakIndent: null,
+		name: null
 	});
 	return (
 		`${i}${cnst} d${_}=${_}Object.getOwnPropertyDescriptor(e,${_}k);${n}` +
@@ -308,6 +300,3 @@ const getFrozen = (fragment: string, freeze: boolean) =>
 	freeze ? `Object.freeze(${fragment})` : fragment;
 
 export const HELPER_NAMES = Object.keys(HELPER_GENERATORS);
-
-const wrapBracesIfNeeded = (code: string, needsBraces: boolean | undefined, _: string): string =>
-	needsBraces ? `{${_}${code}${_}` : code;