1 files changed, 96 insertions, 0 deletions
diff --git a/tools/node_modules/eslint/lib/rules/prefer-spread.js b/tools/node_modules/eslint/lib/rules/prefer-spread.js
new file mode 100644
index 0000000000..c111d5f98e
--- /dev/null
+++ b/tools/node_modules/eslint/lib/rules/prefer-spread.js
@@ -0,0 +1,96 @@
+/**
+ * @fileoverview A rule to suggest using of the spread operator instead of `.apply()`.
+ * @author Toru Nagashima
+ */
+
+"use strict";
+
+const astUtils = require("../ast-utils");
+
+//------------------------------------------------------------------------------
+// Helpers
+//------------------------------------------------------------------------------
+
+/**
+ * Checks whether or not a node is a `.apply()` for variadic.
+ * @param {ASTNode} node - A CallExpression node to check.
+ * @returns {boolean} Whether or not the node is a `.apply()` for variadic.
+ */
+function isVariadicApplyCalling(node) {
+    return (
+        node.callee.type === "MemberExpression" &&
+        node.callee.property.type === "Identifier" &&
+        node.callee.property.name === "apply" &&
+        node.callee.computed === false &&
+        node.arguments.length === 2 &&
+        node.arguments[1].type !== "ArrayExpression" &&
+        node.arguments[1].type !== "SpreadElement"
+    );
+}
+
+
+/**
+ * Checks whether or not `thisArg` is not changed by `.apply()`.
+ * @param {ASTNode|null} expectedThis - The node that is the owner of the applied function.
+ * @param {ASTNode} thisArg - The node that is given to the first argument of the `.apply()`.
+ * @param {RuleContext} context - The ESLint rule context object.
+ * @returns {boolean} Whether or not `thisArg` is not changed by `.apply()`.
+ */
+function isValidThisArg(expectedThis, thisArg, context) {
+    if (!expectedThis) {
+        return astUtils.isNullOrUndefined(thisArg);
+    }
+    return astUtils.equalTokens(expectedThis, thisArg, context);
+}
+
+//------------------------------------------------------------------------------
+// Rule Definition
+//------------------------------------------------------------------------------
+
+module.exports = {
+    meta: {
+        docs: {
+            description: "require spread operators instead of `.apply()`",
+            category: "ECMAScript 6",
+            recommended: false
+        },
+
+        schema: [],
+
+        fixable: "code"
+    },
+
+    create(context) {
+        const sourceCode = context.getSourceCode();
+
+        return {
+            CallExpression(node) {
+                if (!isVariadicApplyCalling(node)) {
+                    return;
+                }
+
+                const applied = node.callee.object;
+                const expectedThis = (applied.type === "MemberExpression") ? applied.object : null;
+                const thisArg = node.arguments[0];
+
+                if (isValidThisArg(expectedThis, thisArg, sourceCode)) {
+                    context.report({
+                        node,
+                        message: "Use the spread operator instead of '.apply()'.",
+                        fix(fixer) {
+                            if (expectedThis && expectedThis.type !== "Identifier") {
+
+                                // Don't fix cases where the `this` value could be a computed expression.
+                                return null;
+                            }
+
+                            const propertyDot = sourceCode.getFirstTokenBetween(applied, node.callee.property, token => token.value === ".");
+
+                            return fixer.replaceTextRange([propertyDot.range[0], node.range[1]], `(...${sourceCode.getText(node.arguments[1])})`);
+                        }
+                    });
+                }
+            }
+        };
+    }
+};