--- /dev/null
+/**
+ * @fileoverview Rule to enforce the position of line comments
+ * @author Alberto RodrÃguez
+ */
+"use strict";
+
+const astUtils = require("./utils/ast-utils");
+
+//------------------------------------------------------------------------------
+// Rule Definition
+//------------------------------------------------------------------------------
+
+module.exports = {
+ meta: {
+ type: "layout",
+
+ docs: {
+ description: "enforce position of line comments",
+ category: "Stylistic Issues",
+ recommended: false,
+ url: "https://eslint.org/docs/rules/line-comment-position"
+ },
+
+ schema: [
+ {
+ oneOf: [
+ {
+ enum: ["above", "beside"]
+ },
+ {
+ type: "object",
+ properties: {
+ position: {
+ enum: ["above", "beside"]
+ },
+ ignorePattern: {
+ type: "string"
+ },
+ applyDefaultPatterns: {
+ type: "boolean"
+ },
+ applyDefaultIgnorePatterns: {
+ type: "boolean"
+ }
+ },
+ additionalProperties: false
+ }
+ ]
+ }
+ ],
+ messages: {
+ above: "Expected comment to be above code.",
+ beside: "Expected comment to be beside code."
+ }
+ },
+
+ create(context) {
+ const options = context.options[0];
+
+ let above,
+ ignorePattern,
+ applyDefaultIgnorePatterns = true;
+
+ if (!options || typeof options === "string") {
+ above = !options || options === "above";
+
+ } else {
+ above = !options.position || options.position === "above";
+ ignorePattern = options.ignorePattern;
+
+ if (Object.prototype.hasOwnProperty.call(options, "applyDefaultIgnorePatterns")) {
+ applyDefaultIgnorePatterns = options.applyDefaultIgnorePatterns;
+ } else {
+ applyDefaultIgnorePatterns = options.applyDefaultPatterns !== false;
+ }
+ }
+
+ const defaultIgnoreRegExp = astUtils.COMMENTS_IGNORE_PATTERN;
+ const fallThroughRegExp = /^\s*falls?\s?through/u;
+ const customIgnoreRegExp = new RegExp(ignorePattern, "u");
+ const sourceCode = context.getSourceCode();
+
+ //--------------------------------------------------------------------------
+ // Public
+ //--------------------------------------------------------------------------
+
+ return {
+ Program() {
+ const comments = sourceCode.getAllComments();
+
+ comments.filter(token => token.type === "Line").forEach(node => {
+ if (applyDefaultIgnorePatterns && (defaultIgnoreRegExp.test(node.value) || fallThroughRegExp.test(node.value))) {
+ return;
+ }
+
+ if (ignorePattern && customIgnoreRegExp.test(node.value)) {
+ return;
+ }
+
+ const previous = sourceCode.getTokenBefore(node, { includeComments: true });
+ const isOnSameLine = previous && previous.loc.end.line === node.loc.start.line;
+
+ if (above) {
+ if (isOnSameLine) {
+ context.report({
+ node,
+ messageId: "above"
+ });
+ }
+ } else {
+ if (!isOnSameLine) {
+ context.report({
+ node,
+ messageId: "beside"
+ });
+ }
+ }
+ });
+ }
+ };
+ }
+};