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Diffstat (limited to 'tools/node_modules/eslint/lib/rules/callback-return.js')
-rw-r--r-- | tools/node_modules/eslint/lib/rules/callback-return.js | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/tools/node_modules/eslint/lib/rules/callback-return.js b/tools/node_modules/eslint/lib/rules/callback-return.js new file mode 100644 index 0000000000..0fa7f278a1 --- /dev/null +++ b/tools/node_modules/eslint/lib/rules/callback-return.js @@ -0,0 +1,175 @@ +/** + * @fileoverview Enforce return after a callback. + * @author Jamund Ferguson + */ +"use strict"; + +//------------------------------------------------------------------------------ +// Rule Definition +//------------------------------------------------------------------------------ + +module.exports = { + meta: { + docs: { + description: "require `return` statements after callbacks", + category: "Node.js and CommonJS", + recommended: false + }, + + schema: [{ + type: "array", + items: { type: "string" } + }] + }, + + create(context) { + + const callbacks = context.options[0] || ["callback", "cb", "next"], + sourceCode = context.getSourceCode(); + + //-------------------------------------------------------------------------- + // Helpers + //-------------------------------------------------------------------------- + + /** + * Find the closest parent matching a list of types. + * @param {ASTNode} node The node whose parents we are searching + * @param {Array} types The node types to match + * @returns {ASTNode} The matched node or undefined. + */ + function findClosestParentOfType(node, types) { + if (!node.parent) { + return null; + } + if (types.indexOf(node.parent.type) === -1) { + return findClosestParentOfType(node.parent, types); + } + return node.parent; + } + + /** + * Check to see if a node contains only identifers + * @param {ASTNode} node The node to check + * @returns {boolean} Whether or not the node contains only identifers + */ + function containsOnlyIdentifiers(node) { + if (node.type === "Identifier") { + return true; + } + + if (node.type === "MemberExpression") { + if (node.object.type === "Identifier") { + return true; + } + if (node.object.type === "MemberExpression") { + return containsOnlyIdentifiers(node.object); + } + } + + return false; + } + + /** + * Check to see if a CallExpression is in our callback list. + * @param {ASTNode} node The node to check against our callback names list. + * @returns {boolean} Whether or not this function matches our callback name. + */ + function isCallback(node) { + return containsOnlyIdentifiers(node.callee) && callbacks.indexOf(sourceCode.getText(node.callee)) > -1; + } + + /** + * Determines whether or not the callback is part of a callback expression. + * @param {ASTNode} node The callback node + * @param {ASTNode} parentNode The expression node + * @returns {boolean} Whether or not this is part of a callback expression + */ + function isCallbackExpression(node, parentNode) { + + // ensure the parent node exists and is an expression + if (!parentNode || parentNode.type !== "ExpressionStatement") { + return false; + } + + // cb() + if (parentNode.expression === node) { + return true; + } + + // special case for cb && cb() and similar + if (parentNode.expression.type === "BinaryExpression" || parentNode.expression.type === "LogicalExpression") { + if (parentNode.expression.right === node) { + return true; + } + } + + return false; + } + + //-------------------------------------------------------------------------- + // Public + //-------------------------------------------------------------------------- + + return { + CallExpression(node) { + + // if we're not a callback we can return + if (!isCallback(node)) { + return; + } + + // find the closest block, return or loop + const closestBlock = findClosestParentOfType(node, ["BlockStatement", "ReturnStatement", "ArrowFunctionExpression"]) || {}; + + // if our parent is a return we know we're ok + if (closestBlock.type === "ReturnStatement") { + return; + } + + // arrow functions don't always have blocks and implicitly return + if (closestBlock.type === "ArrowFunctionExpression") { + return; + } + + // block statements are part of functions and most if statements + if (closestBlock.type === "BlockStatement") { + + // find the last item in the block + const lastItem = closestBlock.body[closestBlock.body.length - 1]; + + // if the callback is the last thing in a block that might be ok + if (isCallbackExpression(node, lastItem)) { + + const parentType = closestBlock.parent.type; + + // but only if the block is part of a function + if (parentType === "FunctionExpression" || + parentType === "FunctionDeclaration" || + parentType === "ArrowFunctionExpression" + ) { + return; + } + + } + + // ending a block with a return is also ok + if (lastItem.type === "ReturnStatement") { + + // but only if the callback is immediately before + if (isCallbackExpression(node, closestBlock.body[closestBlock.body.length - 2])) { + return; + } + } + + } + + // as long as you're the child of a function at this point you should be asked to return + if (findClosestParentOfType(node, ["FunctionDeclaration", "FunctionExpression", "ArrowFunctionExpression"])) { + context.report({ node, message: "Expected return with your callback function." }); + } + + } + + }; + } +}; |