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node_modules/eslint/lib/rules/implicit-arrow-linebreak.js 3.11 KB
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  /**
   * @fileoverview enforce the location of arrow function bodies
   * @author Sharmila Jesupaul
   */
  "use strict";
  
  //------------------------------------------------------------------------------
  // Rule Definition
  //------------------------------------------------------------------------------
  module.exports = {
      meta: {
          docs: {
              description: "enforce the location of arrow function bodies",
              category: "Stylistic Issues",
              recommended: false,
              url: "https://eslint.org/docs/rules/implicit-arrow-linebreak"
          },
          fixable: "whitespace",
          schema: [
              {
                  enum: ["beside", "below"]
              }
          ]
      },
  
      create(context) {
          const sourceCode = context.getSourceCode();
  
          //----------------------------------------------------------------------
          // Helpers
          //----------------------------------------------------------------------
          /**
           * Gets the applicable preference for a particular keyword
           * @returns {string} The applicable option for the keyword, e.g. 'beside'
           */
          function getOption() {
              return context.options[0] || "beside";
          }
  
          /**
           * Validates the location of an arrow function body
           * @param {ASTNode} node The arrow function body
           * @param {string} keywordName The applicable keyword name for the arrow function body
           * @returns {void}
           */
          function validateExpression(node) {
              const option = getOption();
  
              let tokenBefore = sourceCode.getTokenBefore(node.body);
              const hasParens = tokenBefore.value === "(";
  
              if (node.type === "BlockStatement") {
                  return;
              }
  
              let fixerTarget = node.body;
  
              if (hasParens) {
  
                  // Gets the first token before the function body that is not an open paren
                  tokenBefore = sourceCode.getTokenBefore(node.body, token => token.value !== "(");
                  fixerTarget = sourceCode.getTokenAfter(tokenBefore);
              }
  
              if (tokenBefore.loc.end.line === fixerTarget.loc.start.line && option === "below") {
                  context.report({
                      node: fixerTarget,
                      message: "Expected a linebreak before this expression.",
                      fix: fixer => fixer.insertTextBefore(fixerTarget, "\n")
                  });
              } else if (tokenBefore.loc.end.line !== fixerTarget.loc.start.line && option === "beside") {
                  context.report({
                      node: fixerTarget,
                      message: "Expected no linebreak before this expression.",
                      fix: fixer => fixer.replaceTextRange([tokenBefore.range[1], fixerTarget.range[0]], " ")
                  });
              }
          }
  
          //----------------------------------------------------------------------
          // Public
          //----------------------------------------------------------------------
          return {
              ArrowFunctionExpression: node => validateExpression(node)
          };
      }
  };