babel-eslint.js

var assert = require("assert");
var babelEslint = require("..");
var espree = require("espree");
var escope = require("eslint-scope");
var util = require("util");
var unpad = require("dedent");
var assertImplementsAST = require("./fixtures/assert-implements-ast");

function lookup(obj, keypath, backwardsDepth) {
  if (!keypath) {
    return obj;
  }

  return keypath
    .split(".")
    .slice(0, -1 * backwardsDepth)
    .reduce((base, segment) => {
      return base && base[segment], obj;
    });
}

function parseAndAssertSame(code) {
  code = unpad(code);
  var esAST = espree.parse(code, {
    ecmaFeatures: {
      // enable JSX parsing
      jsx: true,
      // enable return in global scope
      globalReturn: true,
      // enable implied strict mode (if ecmaVersion >= 5)
      impliedStrict: true,
      // allow experimental object rest/spread
      experimentalObjectRestSpread: true,
    },
    tokens: true,
    loc: true,
    range: true,
    comment: true,
    attachComment: true,
    ecmaVersion: 2018,
    sourceType: "module",
  });
  var babelAST = babelEslint.parseForESLint(code, {
    eslintVisitorKeys: true,
    eslintScopeManager: true,
  }).ast;
  try {
    assertImplementsAST(esAST, babelAST);
  } catch (err) {
    var traversal = err.message.slice(3, err.message.indexOf(":"));
    err.message += unpad(`
      espree:
      ${util.inspect(lookup(esAST, traversal, 2), {
        depth: err.depth,
        colors: true,
      })}
      babel-eslint:
      ${util.inspect(lookup(babelAST, traversal, 2), {
        depth: err.depth,
        colors: true,
      })}
    `);
    throw err;
  }
  // assert.equal(esAST, babAST);
}

describe("babel-to-estree", () => {
  describe("compatibility", () => {
    it("should allow ast.analyze to be called without options", function() {
      var esAST = babelEslint.parseForESLint("`test`", {
        eslintScopeManager: true,
        eslintVisitorKeys: true,
      }).ast;

      assert.doesNotThrow(
        () => {
          escope.analyze(esAST);
        },
        TypeError,
        "Should allow no options argument."
      );
    });
  });

  describe("templates", () => {
    it("empty template string", () => {
      parseAndAssertSame("``");
    });

    it("template string", () => {
      parseAndAssertSame("`test`");
    });

    it("template string using $", () => {
      parseAndAssertSame("`$`");
    });

    it("template string with expression", () => {
      parseAndAssertSame("`${a}`");
    });

    it("template string with multiple expressions", () => {
      parseAndAssertSame("`${a}${b}${c}`");
    });

    it("template string with expression and strings", () => {
      parseAndAssertSame("`a${a}a`");
    });

    it("template string with binary expression", () => {
      parseAndAssertSame("`a${a + b}a`");
    });

    it("tagged template", () => {
      parseAndAssertSame("jsx`<Button>Click</Button>`");
    });

    it("tagged template with expression", () => {
      parseAndAssertSame("jsx`<Button>Hi ${name}</Button>`");
    });

    it("tagged template with new operator", () => {
      parseAndAssertSame("new raw`42`");
    });

    it("template with nested function/object", () => {
      parseAndAssertSame(
        "`outer${{x: {y: 10}}}bar${`nested${function(){return 1;}}endnest`}end`"
      );
    });

    it("template with braces inside and outside of template string #96", () => {
      parseAndAssertSame(
        "if (a) { var target = `{}a:${webpackPort}{}}}}`; } else { app.use(); }"
      );
    });

    it("template also with braces #96", () => {
      parseAndAssertSame(`
        export default function f1() {
          function f2(foo) {
            const bar = 3;
            return \`\${foo} \${bar}\`;
          }
          return f2;
        }
      `);
    });

    it("template with destructuring #31", () => {
      parseAndAssertSame(`
        module.exports = {
          render() {
            var {name} = this.props;
            return Math.max(null, \`Name: \${name}, Name: \${name}\`);
          }
        };
      `);
    });
  });

  it("simple expression", () => {
    parseAndAssertSame("a = 1");
  });

  it("logical NOT", () => {
    parseAndAssertSame("!0");
  });

  it("bitwise NOT", () => {
    parseAndAssertSame("~0");
  });

  it("class declaration", () => {
    parseAndAssertSame("class Foo {}");
  });

  it("class expression", () => {
    parseAndAssertSame("var a = class Foo {}");
  });

  it("jsx expression", () => {
    parseAndAssertSame("<App />");
  });

  it("jsx expression with 'this' as identifier", () => {
    parseAndAssertSame("<this />");
  });

  it("jsx expression with a dynamic attribute", () => {
    parseAndAssertSame("<App foo={bar} />");
  });

  it("jsx expression with a member expression as identifier", () => {
    parseAndAssertSame("<foo.bar />");
  });

  it("jsx expression with spread", () => {
    parseAndAssertSame("var myDivElement = <div {...this.props} />;");
  });

  it("empty jsx text", () => {
    parseAndAssertSame("<a></a>");
  });

  it("jsx text with content", () => {
    parseAndAssertSame("<a>Hello, world!</a>");
  });

  it("nested jsx", () => {
    parseAndAssertSame("<div>\n<h1>Wat</h1>\n</div>");
  });

  it("default import", () => {
    parseAndAssertSame('import foo from "foo";');
  });

  it("import specifier", () => {
    parseAndAssertSame('import { foo } from "foo";');
  });

  it("import specifier with name", () => {
    parseAndAssertSame('import { foo as bar } from "foo";');
  });

  it("import bare", () => {
    parseAndAssertSame('import "foo";');
  });

  it("export default class declaration", () => {
    parseAndAssertSame("export default class Foo {}");
  });

  it("export default class expression", () => {
    parseAndAssertSame("export default class {}");
  });

  it("export default function declaration", () => {
    parseAndAssertSame("export default function Foo() {}");
  });

  it("export default function expression", () => {
    parseAndAssertSame("export default function () {}");
  });

  it("export all", () => {
    parseAndAssertSame('export * from "foo";');
  });

  it("export named", () => {
    parseAndAssertSame("export { foo };");
  });

  it("export named alias", () => {
    parseAndAssertSame("export { foo as bar };");
  });

  // Espree doesn't support the optional chaining operator yet
  it("optional chaining operator (token)", () => {
    const code = "foo?.bar";
    var babelAST = babelEslint.parseForESLint(code, {
      eslintVisitorKeys: true,
      eslintScopeManager: true,
    }).ast;
    assert.strictEqual(babelAST.tokens[1].type, "Punctuator");
  });

  // Espree doesn't support the nullish coalescing operator yet
  it("nullish coalescing operator (token)", () => {
    const code = "foo ?? bar";
    var babelAST = babelEslint.parseForESLint(code, {
      eslintVisitorKeys: true,
      eslintScopeManager: true,
    }).ast;
    assert.strictEqual(babelAST.tokens[1].type, "Punctuator");
  });

  // Espree doesn't support the pipeline operator yet
  it("pipeline operator (token)", () => {
    const code = "foo |> bar";
    var babelAST = babelEslint.parseForESLint(code, {
      eslintVisitorKeys: true,
      eslintScopeManager: true,
    }).ast;
    assert.strictEqual(babelAST.tokens[1].type, "Punctuator");
  });

  it.skip("empty program with line comment", () => {
    parseAndAssertSame("// single comment");
  });

  it.skip("empty program with block comment", () => {
    parseAndAssertSame("  /* multiline\n * comment\n*/");
  });

  it("line comments", () => {
    parseAndAssertSame(`
      // single comment
      var foo = 15; // comment next to statement
      // second comment after statement
    `);
  });

  it("block comments", () => {
    parseAndAssertSame(`
      /* single comment */
      var foo = 15; /* comment next to statement */
      /*
       * multiline
       * comment
       */
    `);
  });

  it("block comments #124", () => {
    parseAndAssertSame(`
      React.createClass({
        render() {
          // return (
          //   <div />
          // ); // <-- this is the line that is reported
        }
      });
    `);
  });

  it("null", () => {
    parseAndAssertSame("null");
  });

  it("boolean", () => {
    parseAndAssertSame("if (true) {} else if (false) {}");
  });

  it("regexp", () => {
    parseAndAssertSame("/affix-top|affix-bottom|affix|[a-z]/");
  });

  it("regexp", () => {
    parseAndAssertSame("const foo = /foo/;");
  });

  it("regexp y flag", () => {
    parseAndAssertSame("const foo = /foo/y;");
  });

  it("regexp u flag", () => {
    parseAndAssertSame("const foo = /foo/u;");
  });

  it("regexp in a template string", () => {
    parseAndAssertSame('`${/\\d/.exec("1")[0]}`');
  });

  it("first line is empty", () => {
    parseAndAssertSame('\nimport Immutable from "immutable";');
  });

  it("empty", () => {
    parseAndAssertSame("");
  });

  it("jsdoc", () => {
    parseAndAssertSame(`
      /**
      * @param {object} options
      * @return {number}
      */
      const test = function({ a, b, c }) {
        return a + b + c;
      };
      module.exports = test;
    `);
  });

  it("empty block with comment", () => {
    parseAndAssertSame(`
      function a () {
        try {
          b();
        } catch (e) {
          // asdf
        }
      }
    `);
  });

  describe("babel tests", () => {
    it("MethodDefinition", () => {
      parseAndAssertSame(`
        export default class A {
          a() {}
        }
      `);
    });

    it("MethodDefinition 2", () => {
      parseAndAssertSame(
        "export default class Bar { get bar() { return 42; }}"
      );
    });

    it("ClassMethod", () => {
      parseAndAssertSame(`
        class A {
          constructor() {
          }
        }
      `);
    });

    it("ClassMethod multiple params", () => {
      parseAndAssertSame(`
        class A {
          constructor(a, b, c) {
          }
        }
      `);
    });

    it("ClassMethod multiline", () => {
      parseAndAssertSame(`
        class A {
          constructor (
            a,
            b,
            c
          )

          {

          }
        }
      `);
    });

    it("ClassMethod oneline", () => {
      parseAndAssertSame("class A { constructor(a, b, c) {} }");
    });

    it("ObjectMethod", () => {
      parseAndAssertSame(`
        var a = {
          b(c) {
          }
        }
      `);
    });

    it("do not allow import export everywhere", () => {
      assert.throws(() => {
        parseAndAssertSame('function F() { import a from "a"; }');
      }, /SyntaxError: 'import' and 'export' may only appear at the top level/);
    });

    it("return outside function", () => {
      parseAndAssertSame("return;");
    });

    it("super outside method", () => {
      parseAndAssertSame("function F() { super(); }");
    });

    it("StringLiteral", () => {
      parseAndAssertSame("");
      parseAndAssertSame("");
      parseAndAssertSame("a");
    });

    it("getters and setters", () => {
      parseAndAssertSame("class A { get x ( ) { ; } }");
      parseAndAssertSame(`
        class A {
          get x(
          )
          {
            ;
          }
        }
      `);
      parseAndAssertSame("class A { set x (a) { ; } }");
      parseAndAssertSame(`
        class A {
          set x(a
          )
          {
            ;
          }
        }
      `);
      parseAndAssertSame(`
        var B = {
          get x () {
            return this.ecks;
          },
          set x (ecks) {
            this.ecks = ecks;
          }
        };
      `);
    });

    it("RestOperator", () => {
      parseAndAssertSame("var { a, ...b } = c");
      parseAndAssertSame("var [ a, ...b ] = c");
      parseAndAssertSame("var a = function (...b) {}");
    });

    it("SpreadOperator", () => {
      parseAndAssertSame("var a = { b, ...c }");
      parseAndAssertSame("var a = [ a, ...b ]");
      parseAndAssertSame("var a = sum(...b)");
    });

    it("Async/Await", () => {
      parseAndAssertSame(`
        async function a() {
          await 1;
        }
      `);
    });
  });
});

describe("Public API", () => {
  it("exports a parseNoPatch function", () => {
    assertImplementsAST(
      espree.parse("foo"),
      babelEslint.parseNoPatch("foo", {})
    );
  });
});