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lines-between-class-members.js 5.67 KiB
/**
 * @fileoverview Rule to check empty newline between class members
 * @author 薛定谔的猫<hh_2013@foxmail.com>
 */
"use strict";
const astUtils = require("./utils/ast-utils");
//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------
module.exports = {
    meta: {
        type: "layout",
        docs: {
            description: "require or disallow an empty line between class members",
            category: "Stylistic Issues",
            recommended: false,
            url: "https://eslint.org/docs/rules/lines-between-class-members"
        fixable: "whitespace",
        schema: [
                enum: ["always", "never"]
                type: "object",
                properties: {
                    exceptAfterSingleLine: {
                        type: "boolean",
                        default: false
                additionalProperties: false
        messages: {
            never: "Unexpected blank line between class members.",
            always: "Expected blank line between class members."
    create(context) {
        const options = [];
        options[0] = context.options[0] || "always";
        options[1] = context.options[1] || { exceptAfterSingleLine: false };
        const sourceCode = context.getSourceCode();
        /**
         * Return the last token among the consecutive tokens that have no exceed max line difference in between, before the first token in the next member.
         * @param {Token} prevLastToken The last token in the previous member node.
         * @param {Token} nextFirstToken The first token in the next member node.
         * @param {number} maxLine The maximum number of allowed line difference between consecutive tokens.
         * @returns {Token} The last token among the consecutive tokens.
        function findLastConsecutiveTokenAfter(prevLastToken, nextFirstToken, maxLine) {
            const after = sourceCode.getTokenAfter(prevLastToken, { includeComments: true });
            if (after !== nextFirstToken && after.loc.start.line - prevLastToken.loc.end.line <= maxLine) {
                return findLastConsecutiveTokenAfter(after, nextFirstToken, maxLine);
            return prevLastToken;
/** * Return the first token among the consecutive tokens that have no exceed max line difference in between, after the last token in the previous member. * @param {Token} nextFirstToken The first token in the next member node. * @param {Token} prevLastToken The last token in the previous member node. * @param {number} maxLine The maximum number of allowed line difference between consecutive tokens. * @returns {Token} The first token among the consecutive tokens. */ function findFirstConsecutiveTokenBefore(nextFirstToken, prevLastToken, maxLine) { const before = sourceCode.getTokenBefore(nextFirstToken, { includeComments: true }); if (before !== prevLastToken && nextFirstToken.loc.start.line - before.loc.end.line <= maxLine) { return findFirstConsecutiveTokenBefore(before, prevLastToken, maxLine); } return nextFirstToken; } /** * Checks if there is a token or comment between two tokens. * @param {Token} before The token before. * @param {Token} after The token after. * @returns {boolean} True if there is a token or comment between two tokens. */ function hasTokenOrCommentBetween(before, after) { return sourceCode.getTokensBetween(before, after, { includeComments: true }).length !== 0; } return { ClassBody(node) { const body = node.body; for (let i = 0; i < body.length - 1; i++) { const curFirst = sourceCode.getFirstToken(body[i]); const curLast = sourceCode.getLastToken(body[i]); const nextFirst = sourceCode.getFirstToken(body[i + 1]); const isMulti = !astUtils.isTokenOnSameLine(curFirst, curLast); const skip = !isMulti && options[1].exceptAfterSingleLine; const beforePadding = findLastConsecutiveTokenAfter(curLast, nextFirst, 1); const afterPadding = findFirstConsecutiveTokenBefore(nextFirst, curLast, 1); const isPadded = afterPadding.loc.start.line - beforePadding.loc.end.line > 1; const hasTokenInPadding = hasTokenOrCommentBetween(beforePadding, afterPadding); const curLineLastToken = findLastConsecutiveTokenAfter(curLast, nextFirst, 0); if ((options[0] === "always" && !skip && !isPadded) || (options[0] === "never" && isPadded)) { context.report({ node: body[i + 1], messageId: isPadded ? "never" : "always", fix(fixer) { if (hasTokenInPadding) { return null; } return isPadded ? fixer.replaceTextRange([beforePadding.range[1], afterPadding.range[0]], "\n") : fixer.insertTextAfter(curLineLastToken, "\n"); } }); } } } }; } };