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node_modules/eslint/lib/rules/newline-per-chained-call.js 3.43 KB
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  /**
   * @fileoverview Rule to ensure newline per method call when chaining calls
   * @author Rajendra Patil
   * @author Burak Yigit Kaya
   */
  
  "use strict";
  
  const astUtils = require("../ast-utils");
  
  //------------------------------------------------------------------------------
  // Rule Definition
  //------------------------------------------------------------------------------
  
  module.exports = {
      meta: {
          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
                  }
              },
              additionalProperties: false
          }]
      },
  
      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) {
              return node.computed ? "[" : ".";
          }
  
          /**
           * 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) {
                  if (!node.callee || node.callee.type !== "MemberExpression") {
                      return;
                  }
  
                  const callee = node.callee;
                  let parent = callee.object;
                  let depth = 1;
  
                  while (parent && parent.callee) {
                      depth += 1;
                      parent = parent.callee.object;
                  }
  
                  if (depth > ignoreChainWithDepth && astUtils.isTokenOnSameLine(callee.object, callee.property)) {
                      context.report({
                          node: callee.property,
                          loc: callee.property.loc.start,
                          message: "Expected line break before `{{callee}}`.",
                          data: {
                              callee: getPropertyText(callee)
                          },
                          fix(fixer) {
                              const firstTokenAfterObject = sourceCode.getTokenAfter(callee.object, astUtils.isNotClosingParenToken);
  
                              return fixer.insertTextBefore(firstTokenAfterObject, "\n");
                          }
                      });
                  }
              }
          };
      }
  };