Add option to skip loading prettierrc (#83)

Author: eliperelman

Diff for: README.md

@@ -141,6 +141,24 @@ You can then set Prettier's own options inside a `.prettierrc` file.
     ```
 
     _This option is useful if you're migrating a large codebase and already use pragmas like `@flow`._
+  
+  - An object with the following options
+  
+    - `pragma`: Also sets the aforementioned `pragma`: a string with a pragma that triggers this rule. By default, this rule applies to all files. However, if you set a pragma (this option), only files with that pragma in the heading docblock will be checked. All pragmas must start with `@`.
+    
+      ```json
+      "prettier/prettier": ["error", null, {
+        "pragma": "@prettier"
+      }]
+      ```
+      
+    - `usePrettierrc`: Enables loading of the Prettier configuration file, (default: `true`). May be useful if you are using multiple tools that conflict with each other, or do not wish to mix your ESLint settings with your Prettier configuration.
+    
+      ```json
+      "prettier/prettier": ["error", null, {
+        "usePrettierrc": false
+      }]
+      ```
 
 * The rule is autofixable -- if you run `eslint` with the `--fix` flag, your code will be formatted according to `prettier` style.
 

Diff for: eslint-plugin-prettier.js

@@ -282,6 +282,25 @@ function reportReplace(context, offset, deleteText, insertText) {
   });
 }
 
+/**
+ * Get the pragma from the ESLint rule context.
+ * @param {RuleContext} context - The ESLint rule context.
+ * @returns {string|null}
+ */
+function getPragma(context) {
+  const pluginOptions = context.options[1];
+
+  if (!pluginOptions) {
+    return null;
+  }
+
+  const pragmaRef =
+    typeof pluginOptions === 'string' ? pluginOptions : pluginOptions.pragma;
+
+  // Remove leading @
+  return pragmaRef ? pragmaRef.slice(1) : null;
+}
+
 // ------------------------------------------------------------------------------
 //  Module Definition
 // ------------------------------------------------------------------------------
@@ -313,15 +332,26 @@ module.exports = {
               { type: 'object', properties: {}, additionalProperties: true }
             ]
           },
-          // Pragma:
-          { type: 'string', pattern: '^@\\w+$' }
+          {
+            anyOf: [
+              // Pragma:
+              { type: 'string', pattern: '^@\\w+$' },
+              {
+                type: 'object',
+                properties: {
+                  pragma: { type: 'string', pattern: '^@\\w+$' },
+                  usePrettierrc: { type: 'boolean' }
+                },
+                additionalProperties: true
+              }
+            ]
+          }
         ]
       },
       create(context) {
-        const pragma = context.options[1]
-          ? context.options[1].slice(1) // Remove leading @
-          : null;
-
+        const pragma = getPragma(context);
+        const usePrettierrc =
+          !context.options[1] || context.options[1].usePrettierrc !== false;
         const sourceCode = context.getSourceCode();
         const source = sourceCode.text;
 
@@ -365,7 +395,9 @@ module.exports = {
                 ? FB_PRETTIER_OPTIONS
                 : context.options[0];
             const prettierRcOptions =
-              prettier.resolveConfig && prettier.resolveConfig.sync
+              usePrettierrc &&
+              prettier.resolveConfig &&
+              prettier.resolveConfig.sync
                 ? prettier.resolveConfig.sync(context.getFilename())
                 : null;
             const prettierOptions = Object.assign(

Diff for: test/prettier.js

@@ -41,6 +41,11 @@ ruleTester.run('prettier', rule, {
     { code: `/** @format */\n('');\n`, options: ['fb', '@format'] },
     // Shebang with pragma.
     { code: `#!/bin/node\n/** @format */\n"";\n`, options: [null, '@format'] },
+    // Shebang with pragma from options.
+    {
+      code: `#!/bin/node\n/** @format */\n"";\n`,
+      options: [null, { pragma: '@format' }]
+    },
     // Single quote from .prettierrc.
     { code: `'';\n`, filename: getPrettierRcJsFilename('single-quote') },
     // Override .prettierrc from object option.
@@ -54,6 +59,12 @@ ruleTester.run('prettier', rule, {
       code: `('');\n`,
       filename: getPrettierRcJsFilename('double-quote'),
       options: ['fb']
+    },
+    // Only use options from plugin, skipping .prettierrc
+    {
+      code: `var foo = {bar: 0};\n`,
+      filename: getPrettierRcJsFilename('bracket-spacing'),
+      options: [{ bracketSpacing: false }, { usePrettierrc: false }]
     }
   ],
   invalid: [