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Diffstat (limited to 'tools/node_modules/eslint/lib/rules/newline-before-return.js')
| -rw-r--r-- | tools/node_modules/eslint/lib/rules/newline-before-return.js | 210 |
1 files changed, 210 insertions, 0 deletions
diff --git a/tools/node_modules/eslint/lib/rules/newline-before-return.js b/tools/node_modules/eslint/lib/rules/newline-before-return.js new file mode 100644 index 0000000000..02bd66db13 --- /dev/null +++ b/tools/node_modules/eslint/lib/rules/newline-before-return.js @@ -0,0 +1,210 @@ +/** + * @fileoverview Rule to require newlines before `return` statement + * @author Kai Cataldo + * @deprecated + */ +"use strict"; + +//------------------------------------------------------------------------------ +// Rule Definition +//------------------------------------------------------------------------------ + +module.exports = { + meta: { + docs: { + description: "require an empty line before `return` statements", + category: "Stylistic Issues", + recommended: false, + replacedBy: ["padding-line-between-statements"] + }, + fixable: "whitespace", + schema: [], + deprecated: true + }, + + create(context) { + const sourceCode = context.getSourceCode(); + + //-------------------------------------------------------------------------- + // Helpers + //-------------------------------------------------------------------------- + + /** + * Tests whether node is preceded by supplied tokens + * @param {ASTNode} node - node to check + * @param {array} testTokens - array of tokens to test against + * @returns {boolean} Whether or not the node is preceded by one of the supplied tokens + * @private + */ + function isPrecededByTokens(node, testTokens) { + const tokenBefore = sourceCode.getTokenBefore(node); + + return testTokens.some(token => tokenBefore.value === token); + } + + /** + * Checks whether node is the first node after statement or in block + * @param {ASTNode} node - node to check + * @returns {boolean} Whether or not the node is the first node after statement or in block + * @private + */ + function isFirstNode(node) { + const parentType = node.parent.type; + + if (node.parent.body) { + return Array.isArray(node.parent.body) + ? node.parent.body[0] === node + : node.parent.body === node; + } + + if (parentType === "IfStatement") { + return isPrecededByTokens(node, ["else", ")"]); + } + if (parentType === "DoWhileStatement") { + return isPrecededByTokens(node, ["do"]); + } + if (parentType === "SwitchCase") { + return isPrecededByTokens(node, [":"]); + } + return isPrecededByTokens(node, [")"]); + + } + + /** + * Returns the number of lines of comments that precede the node + * @param {ASTNode} node - node to check for overlapping comments + * @param {number} lineNumTokenBefore - line number of previous token, to check for overlapping comments + * @returns {number} Number of lines of comments that precede the node + * @private + */ + function calcCommentLines(node, lineNumTokenBefore) { + const comments = sourceCode.getCommentsBefore(node); + let numLinesComments = 0; + + if (!comments.length) { + return numLinesComments; + } + + comments.forEach(comment => { + numLinesComments++; + + if (comment.type === "Block") { + numLinesComments += comment.loc.end.line - comment.loc.start.line; + } + + // avoid counting lines with inline comments twice + if (comment.loc.start.line === lineNumTokenBefore) { + numLinesComments--; + } + + if (comment.loc.end.line === node.loc.start.line) { + numLinesComments--; + } + }); + + return numLinesComments; + } + + /** + * Returns the line number of the token before the node that is passed in as an argument + * @param {ASTNode} node - The node to use as the start of the calculation + * @returns {number} Line number of the token before `node` + * @private + */ + function getLineNumberOfTokenBefore(node) { + const tokenBefore = sourceCode.getTokenBefore(node); + let lineNumTokenBefore; + + /** + * Global return (at the beginning of a script) is a special case. + * If there is no token before `return`, then we expect no line + * break before the return. Comments are allowed to occupy lines + * before the global return, just no blank lines. + * Setting lineNumTokenBefore to zero in that case results in the + * desired behavior. + */ + if (tokenBefore) { + lineNumTokenBefore = tokenBefore.loc.end.line; + } else { + lineNumTokenBefore = 0; // global return at beginning of script + } + + return lineNumTokenBefore; + } + + /** + * Checks whether node is preceded by a newline + * @param {ASTNode} node - node to check + * @returns {boolean} Whether or not the node is preceded by a newline + * @private + */ + function hasNewlineBefore(node) { + const lineNumNode = node.loc.start.line; + const lineNumTokenBefore = getLineNumberOfTokenBefore(node); + const commentLines = calcCommentLines(node, lineNumTokenBefore); + + return (lineNumNode - lineNumTokenBefore - commentLines) > 1; + } + + /** + * Checks whether it is safe to apply a fix to a given return statement. + * + * The fix is not considered safe if the given return statement has leading comments, + * as we cannot safely determine if the newline should be added before or after the comments. + * For more information, see: https://github.com/eslint/eslint/issues/5958#issuecomment-222767211 + * + * @param {ASTNode} node - The return statement node to check. + * @returns {boolean} `true` if it can fix the node. + * @private + */ + function canFix(node) { + const leadingComments = sourceCode.getCommentsBefore(node); + const lastLeadingComment = leadingComments[leadingComments.length - 1]; + const tokenBefore = sourceCode.getTokenBefore(node); + + if (leadingComments.length === 0) { + return true; + } + + /* + * if the last leading comment ends in the same line as the previous token and + * does not share a line with the `return` node, we can consider it safe to fix. + * Example: + * function a() { + * var b; //comment + * return; + * } + */ + if (lastLeadingComment.loc.end.line === tokenBefore.loc.end.line && + lastLeadingComment.loc.end.line !== node.loc.start.line) { + return true; + } + + return false; + } + + //-------------------------------------------------------------------------- + // Public + //-------------------------------------------------------------------------- + + return { + ReturnStatement(node) { + if (!isFirstNode(node) && !hasNewlineBefore(node)) { + context.report({ + node, + message: "Expected newline before return statement.", + fix(fixer) { + if (canFix(node)) { + const tokenBefore = sourceCode.getTokenBefore(node); + const newlines = node.loc.start.line === tokenBefore.loc.end.line ? "\n\n" : "\n"; + + return fixer.insertTextBefore(node, newlines); + } + return null; + } + }); + } + } + }; + } +}; |