Make Prettier confing take precedence over XO (#301)

lib/options-manager.js

@@ -137,7 +137,21 @@ const normalizeSpaces = opts => {
 	return typeof opts.space === 'number' ? opts.space : 2;
 };
 
-const mergeWithPrettierConf = opts => {
+const mergeWithPrettierConf = (opts, prettierOpts) => {
+	if ((opts.semicolon === true && prettierOpts.semi === false) ||
+		(opts.semicolon === false && prettierOpts.semi === true)) {
+		throw new Error(`The Prettier config \`semi\` is ${prettierOpts.semi} while XO \`semicolon\` is ${opts.semicolon}`);
+	}
+
+	if (((opts.space === true || typeof opts.space === 'number') && prettierOpts.useTabs === false) ||
+		((opts.space === false || typeof opts.space === 'number') && prettierOpts.useTabs === true)) {
+		throw new Error(`The Prettier config \`useTabs\` is ${prettierOpts.useTabs} while XO \`space\` is ${opts.space}`);
+	}
+
+	if (typeof opts.space === 'number' && typeof prettierOpts.tabWidth === 'number' && opts.space !== prettierOpts.tabWidth) {
+		throw new Error(`The Prettier config \`tabWidth\` is ${prettierOpts.tabWidth} while XO \`space\` is ${opts.space}`);
+	}
+
 	return mergeWith(
 		{},
 		{
@@ -146,8 +160,8 @@ const mergeWithPrettierConf = opts => {
 			bracketSpacing: false,
 			jsxBracketSameLine: false
 		},
-		prettier.resolveConfig.sync(opts.cwd || process.cwd()),
 		{tabWidth: normalizeSpaces(opts), useTabs: !opts.space, semi: opts.semicolon !== false},
+		prettierOpts,
 		mergeFn
 	);
 };
@@ -193,7 +207,7 @@ const buildConfig = opts => {
 		}
 	}
 
-	if (opts.semicolon === false) {
+	if (opts.semicolon === false && !opts.prettier) {
 		config.rules.semi = ['error', 'never'];
 		config.rules['semi-spacing'] = ['error', {
 			before: false,
@@ -257,7 +271,9 @@ const buildConfig = opts => {
 		// The prettier config overrides ESLint stylistic rules that are handled by Prettier
 		config.baseConfig.extends = config.baseConfig.extends.concat('prettier');
 		// The `prettier/prettier` rule reports errors if the code is not formatted in accordance to Prettier
-		config.rules['prettier/prettier'] = ['error', mergeWithPrettierConf(opts)];
+		config.rules['prettier/prettier'] = [
+			'error', mergeWithPrettierConf(opts, prettier.resolveConfig.sync(opts.cwd || process.cwd()) || {})
+		];
 		// If the user has the React, Flowtype or Standard plugin, add the corresponding Prettier rule overrides
 		// See https://github.com/prettier/eslint-config-prettier for the list of plugins overrrides
 		for (const override of ['react', 'flowtype', 'standard']) {

readme.md

@@ -206,7 +206,18 @@ Set it to `false` to enforce no-semicolon style.
 Type: `boolean`<br>
 Default: `false`
 
-Format code with [Prettier](https://github.com/prettier/prettier). The [Prettier options](https://prettier.io/docs/en/options.html) will be read from the [Prettier config](https://prettier.io/docs/en/configuration.html)
+Format code with [Prettier](https://github.com/prettier/prettier).
+
+The [Prettier options](https://prettier.io/docs/en/options.html) will be read from the [Prettier config](https://prettier.io/docs/en/configuration.html) and if **not set** will be determined as follow:
+- [semi](https://prettier.io/docs/en/options.html#semicolons): based on [semicolon](#semicolon) option
+- [useTabs](https://prettier.io/docs/en/options.html#tabs): based on [space](#space) option
+- [tabWidth](https://prettier.io/docs/en/options.html#tab-width): based on [space](#space) option
+- [trailingComma](https://prettier.io/docs/en/options.html#trailing-commas): based on [esnext](#esnext)
+- [singleQuote](https://prettier.io/docs/en/options.html#quotes): `true`
+- [bracketSpacing](https://prettier.io/docs/en/options.html#bracket-spacing): `false`
+- [jsxBracketSameLine](https://prettier.io/docs/en/options.html#jsx-brackets): `false`
+
+If contradicting options are set for both Prettier and XO and error will be thrown.
 
 ### nodeVersion
 

test/options-manager.js

@@ -92,6 +92,12 @@ test('buildConfig: prettier: true', t => {
 		}]});
 	// eslint-prettier-config must always be last
 	t.deepEqual(config.baseConfig.extends.slice(-1), ['prettier']);
+	// Indent rule is not enabled
+	t.is(config.rules.indent, undefined);
+	// Semi rule is not enabled
+	t.is(config.rules.semi, undefined);
+	// Semi-spacing is not enabled
+	t.is(config.rules['semi-spacing'], undefined);
 });
 
 test('buildConfig: prettier: true, semicolon: false', t => {
@@ -107,6 +113,12 @@ test('buildConfig: prettier: true, semicolon: false', t => {
 		tabWidth: 2,
 		trailingComma: 'es5'
 	}]);
+	// Indent rule is not enabled
+	t.is(config.rules.indent, undefined);
+	// Semi rule is not enabled
+	t.is(config.rules.semi, undefined);
+	// Semi-spacing is not enabled
+	t.is(config.rules['semi-spacing'], undefined);
 });
 
 test('buildConfig: prettier: true, space: 4', t => {
@@ -124,6 +136,10 @@ test('buildConfig: prettier: true, space: 4', t => {
 	}]);
 	// Indent rule is not enabled
 	t.is(config.rules.indent, undefined);
+	// Semi rule is not enabled
+	t.is(config.rules.semi, undefined);
+	// Semi-spacing is not enabled
+	t.is(config.rules['semi-spacing'], undefined);
 });
 
 test('buildConfig: prettier: true, esnext: false', t => {
@@ -139,6 +155,12 @@ test('buildConfig: prettier: true, esnext: false', t => {
 		tabWidth: 2,
 		trailingComma: 'none'
 	}]);
+	// Indent rule is not enabled
+	t.is(config.rules.indent, undefined);
+	// Semi rule is not enabled
+	t.is(config.rules.semi, undefined);
+	// Semi-spacing is not enabled
+	t.is(config.rules['semi-spacing'], undefined);
 });
 
 test('buildConfig: prettier: true, space: true', t => {
@@ -156,6 +178,24 @@ test('buildConfig: prettier: true, space: true', t => {
 	}]);
 	// Indent rule is not enabled
 	t.is(config.rules.indent, undefined);
+	// Semi rule is not enabled
+	t.is(config.rules.semi, undefined);
+	// Semi-spacing is not enabled
+	t.is(config.rules['semi-spacing'], undefined);
+});
+
+test('buildConfig: merge with prettier config', t => {
+	const cwd = path.resolve('fixtures', 'prettier');
+	const config = manager.buildConfig({cwd, prettier: true});
+
+	// Sets the `semi` options in `prettier/prettier` based on the XO `semicolon` option
+	t.deepEqual(config.rules['prettier/prettier'], ['error', prettierConfig.prettier]);
+	// Indent rule is not enabled
+	t.is(config.rules.indent, undefined);
+	// Semi rule is not enabled
+	t.is(config.rules.semi, undefined);
+	// Semi-spacing is not enabled
+	t.is(config.rules['semi-spacing'], undefined);
 });
 
 test('buildConfig: engines: undefined', t => {
@@ -237,19 +277,69 @@ test('buildConfig: engines: >=8', t => {
 });
 
 test('mergeWithPrettierConf: use `singleQuote`, `trailingComma`, `bracketSpacing` and `jsxBracketSameLine` from `prettier` config if defined', t => {
-	const cwd = path.resolve('fixtures', 'prettier');
-	const result = manager.mergeWithPrettierConf({cwd});
-	const expected = Object.assign({}, prettierConfig.prettier, {tabWidth: 2, useTabs: true, semi: true});
+	const prettierOpts = {singleQuote: false, trailingComma: 'all', bracketSpacing: false, jsxBracketSameLine: false};
+	const result = manager.mergeWithPrettierConf({}, prettierOpts);
+	const expected = Object.assign({}, prettierOpts, {tabWidth: 2, useTabs: true, semi: true});
 	t.deepEqual(result, expected);
 });
 
 test('mergeWithPrettierConf: determine `tabWidth`, `useTabs`, `semi` from xo config', t => {
-	const cwd = path.resolve('fixtures', 'prettier');
-	const result = manager.mergeWithPrettierConf({cwd, space: 4, semicolon: false});
-	const expected = Object.assign({}, prettierConfig.prettier, {tabWidth: 4, useTabs: false, semi: false});
+	const prettierOpts = {tabWidth: 4, useTabs: false, semi: false};
+	const result = manager.mergeWithPrettierConf({space: 4, semicolon: false}, {});
+	const expected = Object.assign(
+		{bracketSpacing: false, jsxBracketSameLine: false, singleQuote: true, trailingComma: 'es5'},
+		prettierOpts
+	);
+	t.deepEqual(result, expected);
+});
+
+test('mergeWithPrettierConf: determine `tabWidth`, `useTabs`, `semi` from prettier config', t => {
+	const prettierOpts = {useTabs: false, semi: false, tabWidth: 4};
+	const result = manager.mergeWithPrettierConf({}, prettierOpts);
+	const expected = Object.assign(
+		{bracketSpacing: false, jsxBracketSameLine: false, singleQuote: true, trailingComma: 'es5'},
+		prettierOpts
+	);
 	t.deepEqual(result, expected);
 });
 
+test('mergeWithPrettierConf: throw error is `semi`/`semicolon` conflicts', t => {
+	t.throws(() => manager.mergeWithPrettierConf(
+		{semicolon: true},
+		{semi: false}
+	));
+	t.throws(() => manager.mergeWithPrettierConf(
+		{semicolon: false},
+		{semi: true}
+	));
+
+	t.notThrows(() => manager.mergeWithPrettierConf(
+		{semicolon: true},
+		{semi: true}
+	));
+	t.notThrows(() => manager.mergeWithPrettierConf({semicolon: false}, {semi: false}));
+});
+
+test('mergeWithPrettierConf: throw error is `space`/`useTabs` conflicts', t => {
+	t.throws(() => manager.mergeWithPrettierConf({space: true}, {useTabs: false}));
+	t.throws(() => manager.mergeWithPrettierConf({space: 4}, {useTabs: false}));
+	t.throws(() => manager.mergeWithPrettierConf({space: 0}, {useTabs: false}));
+	t.throws(() => manager.mergeWithPrettierConf({space: false}, {useTabs: true}));
+
+	t.notThrows(() => manager.mergeWithPrettierConf({space: false}, {useTabs: false}));
+	t.notThrows(() => manager.mergeWithPrettierConf({space: true}, {useTabs: true}));
+});
+
+test('mergeWithPrettierConf: throw error is `space`/`tabWidth` conflicts', t => {
+	t.throws(() => manager.mergeWithPrettierConf({space: 4}, {tabWidth: 2}));
+	t.throws(() => manager.mergeWithPrettierConf({space: 0}, {tabWidth: 2}));
+	t.throws(() => manager.mergeWithPrettierConf({space: 2}, {tabWidth: 0}));
+
+	t.notThrows(() => manager.mergeWithPrettierConf({space: 4}, {tabWidth: 4}));
+	t.notThrows(() => manager.mergeWithPrettierConf({space: false}, {tabWidth: 4}));
+	t.notThrows(() => manager.mergeWithPrettierConf({space: true}, {tabWidth: 4}));
+});
+
 test('buildConfig: rules', t => {
 	const rules = {'object-curly-spacing': ['error', 'always']};
 	const config = manager.buildConfig({rules});