diff options
Diffstat (limited to 'tools/node_modules/eslint/lib/rules/arrow-body-style.js')
| -rw-r--r-- | tools/node_modules/eslint/lib/rules/arrow-body-style.js | 215 |
1 files changed, 215 insertions, 0 deletions
diff --git a/tools/node_modules/eslint/lib/rules/arrow-body-style.js b/tools/node_modules/eslint/lib/rules/arrow-body-style.js new file mode 100644 index 0000000000..78a391334d --- /dev/null +++ b/tools/node_modules/eslint/lib/rules/arrow-body-style.js @@ -0,0 +1,215 @@ +/** + * @fileoverview Rule to require braces in arrow function body. + * @author Alberto RodrÃguez + */ +"use strict"; + +//------------------------------------------------------------------------------ +// Requirements +//------------------------------------------------------------------------------ + +const astUtils = require("../ast-utils"); + +//------------------------------------------------------------------------------ +// Rule Definition +//------------------------------------------------------------------------------ + +module.exports = { + meta: { + docs: { + description: "require braces around arrow function bodies", + category: "ECMAScript 6", + recommended: false + }, + + schema: { + anyOf: [ + { + type: "array", + items: [ + { + enum: ["always", "never"] + } + ], + minItems: 0, + maxItems: 1 + }, + { + type: "array", + items: [ + { + enum: ["as-needed"] + }, + { + type: "object", + properties: { + requireReturnForObjectLiteral: { type: "boolean" } + }, + additionalProperties: false + } + ], + minItems: 0, + maxItems: 2 + } + ] + }, + + fixable: "code" + }, + + create(context) { + const options = context.options; + const always = options[0] === "always"; + const asNeeded = !options[0] || options[0] === "as-needed"; + const never = options[0] === "never"; + const requireReturnForObjectLiteral = options[1] && options[1].requireReturnForObjectLiteral; + const sourceCode = context.getSourceCode(); + + /** + * Checks whether the given node has ASI problem or not. + * @param {Token} token The token to check. + * @returns {boolean} `true` if it changes semantics if `;` or `}` followed by the token are removed. + */ + function hasASIProblem(token) { + return token && token.type === "Punctuator" && /^[([/`+-]/.test(token.value); + } + + /** + * Gets the closing parenthesis which is the pair of the given opening parenthesis. + * @param {Token} token The opening parenthesis token to get. + * @returns {Token} The found closing parenthesis token. + */ + function findClosingParen(token) { + let node = sourceCode.getNodeByRangeIndex(token.range[1]); + + while (!astUtils.isParenthesised(sourceCode, node)) { + node = node.parent; + } + return sourceCode.getTokenAfter(node); + } + + /** + * Determines whether a arrow function body needs braces + * @param {ASTNode} node The arrow function node. + * @returns {void} + */ + function validate(node) { + const arrowBody = node.body; + + if (arrowBody.type === "BlockStatement") { + const blockBody = arrowBody.body; + + if (blockBody.length !== 1 && !never) { + return; + } + + if (asNeeded && requireReturnForObjectLiteral && blockBody[0].type === "ReturnStatement" && + blockBody[0].argument && blockBody[0].argument.type === "ObjectExpression") { + return; + } + + if (never || asNeeded && blockBody[0].type === "ReturnStatement") { + context.report({ + node, + loc: arrowBody.loc.start, + message: "Unexpected block statement surrounding arrow body.", + fix(fixer) { + const fixes = []; + + if (blockBody.length !== 1 || + blockBody[0].type !== "ReturnStatement" || + !blockBody[0].argument || + hasASIProblem(sourceCode.getTokenAfter(arrowBody)) + ) { + return fixes; + } + + const openingBrace = sourceCode.getFirstToken(arrowBody); + const closingBrace = sourceCode.getLastToken(arrowBody); + const firstValueToken = sourceCode.getFirstToken(blockBody[0], 1); + const lastValueToken = sourceCode.getLastToken(blockBody[0]); + const commentsExist = + sourceCode.commentsExistBetween(openingBrace, firstValueToken) || + sourceCode.commentsExistBetween(lastValueToken, closingBrace); + + /* + * Remove tokens around the return value. + * If comments don't exist, remove extra spaces as well. + */ + if (commentsExist) { + fixes.push( + fixer.remove(openingBrace), + fixer.remove(closingBrace), + fixer.remove(sourceCode.getTokenAfter(openingBrace)) // return keyword + ); + } else { + fixes.push( + fixer.removeRange([openingBrace.range[0], firstValueToken.range[0]]), + fixer.removeRange([lastValueToken.range[1], closingBrace.range[1]]) + ); + } + + /* + * If the first token of the reutrn value is `{`, + * enclose the return value by parentheses to avoid syntax error. + */ + if (astUtils.isOpeningBraceToken(firstValueToken)) { + fixes.push( + fixer.insertTextBefore(firstValueToken, "("), + fixer.insertTextAfter(lastValueToken, ")") + ); + } + + /* + * If the last token of the return statement is semicolon, remove it. + * Non-block arrow body is an expression, not a statement. + */ + if (astUtils.isSemicolonToken(lastValueToken)) { + fixes.push(fixer.remove(lastValueToken)); + } + + return fixes; + } + }); + } + } else { + if (always || (asNeeded && requireReturnForObjectLiteral && arrowBody.type === "ObjectExpression")) { + context.report({ + node, + loc: arrowBody.loc.start, + message: "Expected block statement surrounding arrow body.", + fix(fixer) { + const fixes = []; + const arrowToken = sourceCode.getTokenBefore(arrowBody, astUtils.isArrowToken); + const firstBodyToken = sourceCode.getTokenAfter(arrowToken); + const lastBodyToken = sourceCode.getLastToken(node); + const isParenthesisedObjectLiteral = + astUtils.isOpeningParenToken(firstBodyToken) && + astUtils.isOpeningBraceToken(sourceCode.getTokenAfter(firstBodyToken)); + + // Wrap the value by a block and a return statement. + fixes.push( + fixer.insertTextBefore(firstBodyToken, "{return "), + fixer.insertTextAfter(lastBodyToken, "}") + ); + + // If the value is object literal, remove parentheses which were forced by syntax. + if (isParenthesisedObjectLiteral) { + fixes.push( + fixer.remove(firstBodyToken), + fixer.remove(findClosingParen(firstBodyToken)) + ); + } + + return fixes; + } + }); + } + } + } + + return { + "ArrowFunctionExpression:exit": validate + }; + } +}; |