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newline-per-chained-call.js 3.95 KiB
/**
 * @fileoverview Rule to ensure newline per method call when chaining calls
 * @author Rajendra Patil
 * @author Burak Yigit Kaya
 */
"use strict";
const astUtils = require("./utils/ast-utils");
//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------
module.exports = {
    meta: {
        type: "layout",
        docs: {
            description: "require a newline after each call in a method chain",
            category: "Stylistic Issues",
            recommended: false,
            url: "https://eslint.org/docs/rules/newline-per-chained-call"
        fixable: "whitespace",
        schema: [{
            type: "object",
            properties: {
                ignoreChainWithDepth: {
                    type: "integer",
                    minimum: 1,
                    maximum: 10,
                    default: 2
            additionalProperties: false
        }],
        messages: {
            expected: "Expected line break before `{{callee}}`."
    create(context) {
        const options = context.options[0] || {},
            ignoreChainWithDepth = options.ignoreChainWithDepth || 2;
        const sourceCode = context.getSourceCode();
        /**
         * Get the prefix of a given MemberExpression node.
         * If the MemberExpression node is a computed value it returns a
         * left bracket. If not it returns a period.
         * @param  {ASTNode} node A MemberExpression node to get
         * @returns {string} The prefix of the node.
        function getPrefix(node) {
            if (node.computed) {
                if (node.optional) {
                    return "?.[";
                return "[";
            if (node.optional) {
                return "?.";
            return ".";
/** * Gets the property text of a given MemberExpression node. * If the text is multiline, this returns only the first line. * @param {ASTNode} node A MemberExpression node to get. * @returns {string} The property text of the node. */ function getPropertyText(node) { const prefix = getPrefix(node); const lines = sourceCode.getText(node.property).split(astUtils.LINEBREAK_MATCHER); const suffix = node.computed && lines.length === 1 ? "]" : ""; return prefix + lines[0] + suffix; } return { "CallExpression:exit"(node) { const callee = astUtils.skipChainExpression(node.callee); if (callee.type !== "MemberExpression") { return; } let parent = astUtils.skipChainExpression(callee.object); let depth = 1; while (parent && parent.callee) { depth += 1; parent = astUtils.skipChainExpression(astUtils.skipChainExpression(parent.callee).object); } if (depth > ignoreChainWithDepth && astUtils.isTokenOnSameLine(callee.object, callee.property)) { const firstTokenAfterObject = sourceCode.getTokenAfter(callee.object, astUtils.isNotClosingParenToken); context.report({ node: callee.property, loc: { start: firstTokenAfterObject.loc.start, end: callee.loc.end }, messageId: "expected", data: { callee: getPropertyText(callee) }, fix(fixer) { return fixer.insertTextBefore(firstTokenAfterObject, "\n"); } }); } } }; } };