New: Add eslintIgnore support to package.json (fixes #8458)

docs/user-guide/configuring.md

@@ -775,6 +775,22 @@ You can also use your `.gitignore` file:
 
 Any file that follows the standard ignore file format can be used. Keep in mind that specifying `--ignore-path` means that any existing `.eslintignore` file will not be used. Note that globbing rules in `.eslintignore` follow those of `.gitignore`.
 
+### Using eslintIgnore in package.json
+
+If an `.eslintignore` file is not found and an alternate file is not specified, eslint will look in package.json for an `eslintIgnore` key to check for files to ignore.
+
+    {
+      "name": "mypackage",
+      "version": "0.0.1",
+      "eslintConfig": {
+          "env": {
+              "browser": true,
+              "node": true
+          }
+      },
+      "eslintIgnore": ["hello.js", "world.js"]
+    }
+
 ### Ignored File Warnings
 
 When you pass directories to ESLint, files and directories are silently ignored. If you pass a specific file to ESLint, then you will see a warning indicating that the file was skipped. For example, suppose you have an `.eslintignore` file that looks like this:

lib/ignored-paths.js

@@ -16,7 +16,6 @@ const fs = require("fs"),
 
 const debug = require("debug")("eslint:ignored-paths");
 
-
 //------------------------------------------------------------------------------
 // Constants
 //------------------------------------------------------------------------------
@@ -41,20 +40,38 @@ const DEFAULT_OPTIONS = {
 // Helpers
 //------------------------------------------------------------------------------
 
-
 /**
- * Find an ignore file in the current directory.
+ * Find a file in the current directory.
  * @param {string} cwd Current working directory
+ * @param {string} name File name
  * @returns {string} Path of ignore file or an empty string.
  */
-function findIgnoreFile(cwd) {
+function findFile(cwd, name) {
     cwd = cwd || DEFAULT_OPTIONS.cwd;
 
-    const ignoreFilePath = path.resolve(cwd, ESLINT_IGNORE_FILENAME);
+    const ignoreFilePath = path.resolve(cwd, name);
 
     return fs.existsSync(ignoreFilePath) && fs.statSync(ignoreFilePath).isFile() ? ignoreFilePath : "";
 }
 
+/**
+ * Find an ignore file in the current directory.
+ * @param {string} cwd Current working directory
+ * @returns {string} Path of ignore file or an empty string.
+ */
+function findIgnoreFile(cwd) {
+    return findFile(cwd, ESLINT_IGNORE_FILENAME);
+}
+
+/**
+ * Find an package.json file in the current directory.
+ * @param {string} cwd Current working directory
+ * @returns {string} Path of package.json file or an empty string.
+ */
+function findPackageJSONFile(cwd) {
+    return findFile(cwd, "package.json");
+}
+
 /**
  * Merge options with defaults
  * @param {Object} options Options to merge with DEFAULT_OPTIONS constant
@@ -146,6 +163,37 @@ class IgnoredPaths {
                 this.baseDir = path.dirname(path.resolve(options.cwd, ignorePath));
                 this.addIgnoreFile(this.ig.custom, ignorePath);
                 this.addIgnoreFile(this.ig.default, ignorePath);
+            } else {
+                try {
+
+                    // if the ignoreFile does not exist, check package.json for eslintIgnore
+                    const packageJSONPath = findPackageJSONFile(options.cwd);
+
+                    if (packageJSONPath) {
+                        let packageJSONOptions;
+
+                        try {
+                            packageJSONOptions = JSON.parse(fs.readFileSync(packageJSONPath, "utf8"));
+                        } catch (e) {
+                            debug("Could not read package.json file to check eslintIgnore property");
+                            throw e;
+                        }
+
+                        if (packageJSONOptions.eslintIgnore) {
+                            if (Array.isArray(packageJSONOptions.eslintIgnore)) {
+                                packageJSONOptions.eslintIgnore.forEach(pattern => {
+                                    addPattern(this.ig.custom, pattern);
+                                    addPattern(this.ig.default, pattern);
+                                });
+                            } else {
+                                throw new Error("Package.json eslintIgnore property requires an array of paths");
+                            }
+                        }
+                    }
+                } catch (e) {
+                    debug("Could not find package.json to check eslintIgnore property");
+                    throw e;
+                }
             }
 
             if (options.ignorePattern) {

tests/fixtures/ignored-paths/bad-package-json-ignore/package.json

@@ -0,0 +1,11 @@
+{
+    "name": "mypackage",
+    "version": "0.0.1",
+    "eslintConfig": {
+        "env": {
+            "browser": true,
+            "node": true
+        }
+    },
+    "eslintIgnore": "hello.js"
+}

tests/fixtures/ignored-paths/package-json-ignore/package.json

@@ -0,0 +1,11 @@
+{
+    "name": "mypackage",
+    "version": "0.0.1",
+    "eslintConfig": {
+        "env": {
+            "browser": true,
+            "node": true
+        }
+    },
+    "eslintIgnore": ["hello.js", "world.js"]
+}

tests/fixtures/ignored-paths/package.json

@@ -0,0 +1,11 @@
+{
+    "name": "mypackage",
+    "version": "0.0.1",
+    "eslintConfig": {
+        "env": {
+            "browser": true,
+            "node": true
+        }
+    },
+    "eslintIgnore": ["hello.js", "world.js"]
+}

tests/lib/ignored-paths.js

@@ -165,7 +165,28 @@ describe("IgnoredPaths", () => {
             );
         });
 
+        it("should use package.json's eslintIgnore files if no specified .eslintignore file", () => {
+            const ignoredPaths = new IgnoredPaths({ ignore: true, cwd: getFixturePath("package-json-ignore") });
 
+            assert.isTrue(ignoredPaths.contains("hello.js"));
+            assert.isTrue(ignoredPaths.contains("world.js"));
+        });
+
+        it("should not use package.json's eslintIgnore files if specified .eslintignore file", () => {
+            const ignoredPaths = new IgnoredPaths({ ignore: true, cwd: getFixturePath() });
+
+            assert.isFalse(ignoredPaths.contains("hello.js"));
+            assert.isFalse(ignoredPaths.contains("world.js"));
+            assert.isTrue(ignoredPaths.contains("sampleignorepattern"));
+        });
+
+        it("should error if package.json's eslintIgnore is not an array of file paths", () => {
+            assert.throws(() => {
+                const ignoredPaths = new IgnoredPaths({ ignore: true, cwd: getFixturePath("bad-package-json-ignore") });
+
+                assert.ok(ignoredPaths);
+            }, "Package.json eslintIgnore property requires an array of paths");
+        });
     });
 
     describe("caching file reads", () => {