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author | Michaël Zasso <targos@protonmail.com> | 2017-12-22 16:53:42 +0100 |
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committer | Michaël Zasso <targos@protonmail.com> | 2018-01-11 09:48:05 +0100 |
commit | 3dc30632755713179f345f4af024bd904c6162d0 (patch) | |
tree | f28c4f6dd6dfc5992edf301449d1a371d229755b /tools/node_modules/eslint/lib/rules/no-fallthrough.js | |
parent | a2c7085dd4a8e60d1a47572aca8bb6fcb7a32f88 (diff) | |
download | android-node-v8-3dc30632755713179f345f4af024bd904c6162d0.tar.gz android-node-v8-3dc30632755713179f345f4af024bd904c6162d0.tar.bz2 android-node-v8-3dc30632755713179f345f4af024bd904c6162d0.zip |
tools: move eslint from tools to tools/node_modules
This is required because we need to add the babel-eslint dependency
and it has to be able to resolve "eslint".
babel-eslint is required to support future ES features such as async
iterators and import.meta.
Refs: https://github.com/nodejs/node/pull/17755
PR-URL: https://github.com/nodejs/node/pull/17820
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Diffstat (limited to 'tools/node_modules/eslint/lib/rules/no-fallthrough.js')
-rw-r--r-- | tools/node_modules/eslint/lib/rules/no-fallthrough.js | 135 |
1 files changed, 135 insertions, 0 deletions
diff --git a/tools/node_modules/eslint/lib/rules/no-fallthrough.js b/tools/node_modules/eslint/lib/rules/no-fallthrough.js new file mode 100644 index 0000000000..082e8431d6 --- /dev/null +++ b/tools/node_modules/eslint/lib/rules/no-fallthrough.js @@ -0,0 +1,135 @@ +/** + * @fileoverview Rule to flag fall-through cases in switch statements. + * @author Matt DuVall <http://mattduvall.com/> + */ +"use strict"; + +//------------------------------------------------------------------------------ +// Requirements +//------------------------------------------------------------------------------ + +const lodash = require("lodash"); + +//------------------------------------------------------------------------------ +// Helpers +//------------------------------------------------------------------------------ + +const DEFAULT_FALLTHROUGH_COMMENT = /falls?\s?through/i; + +/** + * Checks whether or not a given node has a fallthrough comment. + * @param {ASTNode} node - A SwitchCase node to get comments. + * @param {RuleContext} context - A rule context which stores comments. + * @param {RegExp} fallthroughCommentPattern - A pattern to match comment to. + * @returns {boolean} `true` if the node has a valid fallthrough comment. + */ +function hasFallthroughComment(node, context, fallthroughCommentPattern) { + const sourceCode = context.getSourceCode(); + const comment = lodash.last(sourceCode.getCommentsBefore(node)); + + return Boolean(comment && fallthroughCommentPattern.test(comment.value)); +} + +/** + * Checks whether or not a given code path segment is reachable. + * @param {CodePathSegment} segment - A CodePathSegment to check. + * @returns {boolean} `true` if the segment is reachable. + */ +function isReachable(segment) { + return segment.reachable; +} + +/** + * Checks whether a node and a token are separated by blank lines + * @param {ASTNode} node - The node to check + * @param {Token} token - The token to compare against + * @returns {boolean} `true` if there are blank lines between node and token + */ +function hasBlankLinesBetween(node, token) { + return token.loc.start.line > node.loc.end.line + 1; +} + +//------------------------------------------------------------------------------ +// Rule Definition +//------------------------------------------------------------------------------ + +module.exports = { + meta: { + docs: { + description: "disallow fallthrough of `case` statements", + category: "Best Practices", + recommended: true + }, + + schema: [ + { + type: "object", + properties: { + commentPattern: { + type: "string" + } + }, + additionalProperties: false + } + ] + }, + + create(context) { + const options = context.options[0] || {}; + let currentCodePath = null; + const sourceCode = context.getSourceCode(); + + /* + * We need to use leading comments of the next SwitchCase node because + * trailing comments is wrong if semicolons are omitted. + */ + let fallthroughCase = null; + let fallthroughCommentPattern = null; + + if (options.commentPattern) { + fallthroughCommentPattern = new RegExp(options.commentPattern); + } else { + fallthroughCommentPattern = DEFAULT_FALLTHROUGH_COMMENT; + } + + return { + onCodePathStart(codePath) { + currentCodePath = codePath; + }, + onCodePathEnd() { + currentCodePath = currentCodePath.upper; + }, + + SwitchCase(node) { + + /* + * Checks whether or not there is a fallthrough comment. + * And reports the previous fallthrough node if that does not exist. + */ + if (fallthroughCase && !hasFallthroughComment(node, context, fallthroughCommentPattern)) { + context.report({ + message: "Expected a 'break' statement before '{{type}}'.", + data: { type: node.test ? "case" : "default" }, + node + }); + } + fallthroughCase = null; + }, + + "SwitchCase:exit"(node) { + const nextToken = sourceCode.getTokenAfter(node); + + /* + * `reachable` meant fall through because statements preceded by + * `break`, `return`, or `throw` are unreachable. + * And allows empty cases and the last case. + */ + if (currentCodePath.currentSegments.some(isReachable) && + (node.consequent.length > 0 || hasBlankLinesBetween(node, nextToken)) && + lodash.last(node.parent.cases) !== node) { + fallthroughCase = node; + } + } + }; + } +}; |