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node_modules/eslint/lib/rules/generator-star-spacing.js 4.85 KB
f7563de62   Palak Handa   first commit
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  /**
   * @fileoverview Rule to check the spacing around the * in generator functions.
   * @author Jamund Ferguson
   */
  
  "use strict";
  
  //------------------------------------------------------------------------------
  // Rule Definition
  //------------------------------------------------------------------------------
  
  module.exports = {
      meta: {
          docs: {
              description: "enforce consistent spacing around `*` operators in generator functions",
              category: "ECMAScript 6",
              recommended: false
          },
  
          fixable: "whitespace",
  
          schema: [
              {
                  oneOf: [
                      {
                          enum: ["before", "after", "both", "neither"]
                      },
                      {
                          type: "object",
                          properties: {
                              before: { type: "boolean" },
                              after: { type: "boolean" }
                          },
                          additionalProperties: false
                      }
                  ]
              }
          ]
      },
  
      create(context) {
  
          const mode = (function(option) {
              if (!option || typeof option === "string") {
                  return {
                      before: { before: true, after: false },
                      after: { before: false, after: true },
                      both: { before: true, after: true },
                      neither: { before: false, after: false }
                  }[option || "before"];
              }
              return option;
          }(context.options[0]));
  
          const sourceCode = context.getSourceCode();
  
          /**
           * Checks if the given token is a star token or not.
           *
           * @param {Token} token - The token to check.
           * @returns {boolean} `true` if the token is a star token.
           */
          function isStarToken(token) {
              return token.value === "*" && token.type === "Punctuator";
          }
  
          /**
           * Gets the generator star token of the given function node.
           *
           * @param {ASTNode} node - The function node to get.
           * @returns {Token} Found star token.
           */
          function getStarToken(node) {
              return sourceCode.getFirstToken(
                  (node.parent.method || node.parent.type === "MethodDefinition") ? node.parent : node,
                  isStarToken
              );
          }
  
          /**
           * Checks the spacing between two tokens before or after the star token.
           * @param {string} side Either "before" or "after".
           * @param {Token} leftToken `function` keyword token if side is "before", or
           *     star token if side is "after".
           * @param {Token} rightToken Star token if side is "before", or identifier
           *     token if side is "after".
           * @returns {void}
           */
          function checkSpacing(side, leftToken, rightToken) {
              if (!!(rightToken.range[0] - leftToken.range[1]) !== mode[side]) {
                  const after = leftToken.value === "*";
                  const spaceRequired = mode[side];
                  const node = after ? leftToken : rightToken;
                  const type = spaceRequired ? "Missing" : "Unexpected";
                  const message = "{{type}} space {{side}} *.";
                  const data = {
                      type,
                      side
                  };
  
                  context.report({
                      node,
                      message,
                      data,
                      fix(fixer) {
                          if (spaceRequired) {
                              if (after) {
                                  return fixer.insertTextAfter(node, " ");
                              }
                              return fixer.insertTextBefore(node, " ");
                          }
                          return fixer.removeRange([leftToken.range[1], rightToken.range[0]]);
                      }
                  });
              }
          }
  
          /**
           * Enforces the spacing around the star if node is a generator function.
           * @param {ASTNode} node A function expression or declaration node.
           * @returns {void}
           */
          function checkFunction(node) {
              if (!node.generator) {
                  return;
              }
  
              const starToken = getStarToken(node);
  
              // Only check before when preceded by `function`|`static` keyword
              const prevToken = sourceCode.getTokenBefore(starToken);
  
              if (prevToken.value === "function" || prevToken.value === "static") {
                  checkSpacing("before", prevToken, starToken);
              }
  
              const nextToken = sourceCode.getTokenAfter(starToken);
  
              checkSpacing("after", starToken, nextToken);
          }
  
          return {
              FunctionDeclaration: checkFunction,
              FunctionExpression: checkFunction
          };
  
      }
  };