text: import traverse from "../lib";
  import { parse } from "@babel/parser";
  import * as t from "@babel/types";
  
  function getPath(code) {
    const ast = parse(code, { plugins: ["flow", "asyncGenerators"] });
    let path;
    traverse(ast, {
      Program: function(_path) {
        path = _path;
        _path.stop();
      },
    });
    return path;
  }
  
  describe("inference", function() {
    describe("baseTypeStrictlyMatches", function() {
      it("it should work with null", function() {
        const path = getPath("var x = null; x === null")
          .get("body")[1]
          .get("expression");
        const left = path.get("left");
        const right = path.get("right");
        const strictMatch = left.baseTypeStrictlyMatches(right);
  
        expect(strictMatch).toBeTruthy();
      });
  
      it("it should work with numbers", function() {
        const path = getPath("var x = 1; x === 2")
          .get("body")[1]
          .get("expression");
        const left = path.get("left");
        const right = path.get("right");
        const strictMatch = left.baseTypeStrictlyMatches(right);
  
        expect(strictMatch).toBeTruthy();
      });
  
      it("it should bail when type changes", function() {
        const path = getPath("var x = 1; if (foo) x = null;else x = 3; x === 2")
          .get("body")[2]
          .get("expression");
        const left = path.get("left");
        const right = path.get("right");
  
        const strictMatch = left.baseTypeStrictlyMatches(right);
  
        expect(strictMatch).toBeFalsy();
      });
  
      it("it should differentiate between null and undefined", function() {
        const path = getPath("var x; x === null")
          .get("body")[1]
          .get("expression");
        const left = path.get("left");
        const right = path.get("right");
        const strictMatch = left.baseTypeStrictlyMatches(right);
  
        expect(strictMatch).toBeFalsy();
      });
    });
    describe("getTypeAnnotation", function() {
      it("should infer from type cast", function() {
        const path = getPath("(x: number)")
          .get("body")[0]
          .get("expression");
        expect(t.isNumberTypeAnnotation(path.getTypeAnnotation())).toBeTruthy();
      });
      it("should infer string from template literal", function() {
        const path = getPath("`hey`")
          .get("body")[0]
          .get("expression");
        expect(t.isStringTypeAnnotation(path.getTypeAnnotation())).toBeTruthy();
      });
      it("should infer number from +x", function() {
        const path = getPath("+x")
          .get("body")[0]
          .get("expression");
        expect(t.isNumberTypeAnnotation(path.getTypeAnnotation())).toBeTruthy();
      });
      it("should infer T from new T", function() {
        const path = getPath("new T")
          .get("body")[0]
          .get("expression");
        const type = path.getTypeAnnotation();
        expect(
          t.isGenericTypeAnnotation(type) && type.id.name === "T",
        ).toBeTruthy();
      });
      it("should infer number from ++x", function() {
        const path = getPath("++x")
          .get("body")[0]
          .get("expression");
        expect(t.isNumberTypeAnnotation(path.getTypeAnnotation())).toBeTruthy();
      });
      it("should infer number from --x", function() {
        const path = getPath("--x")
          .get("body")[0]
          .get("expression");
        expect(t.isNumberTypeAnnotation(path.getTypeAnnotation())).toBeTruthy();
      });
      it("should infer void from void x", function() {
        const path = getPath("void x")
          .get("body")[0]
          .get("expression");
        expect(t.isVoidTypeAnnotation(path.getTypeAnnotation())).toBeTruthy();
      });
      it("should infer string from typeof x", function() {
        const path = getPath("typeof x")
          .get("body")[0]
          .get("expression");
        expect(t.isStringTypeAnnotation(path.getTypeAnnotation())).toBeTruthy();
      });
      it("should infer boolean from !x", function() {
        const path = getPath("!x")
          .get("body")[0]
          .get("expression");
        expect(t.isBooleanTypeAnnotation(path.getTypeAnnotation())).toBeTruthy();
      });
      it("should infer type of sequence expression", function() {
        const path = getPath("a,1")
          .get("body")[0]
          .get("expression");
        expect(t.isNumberTypeAnnotation(path.getTypeAnnotation())).toBeTruthy();
      });
      it("should infer type of logical expression", function() {
        const path = getPath("'a' && 1")
          .get("body")[0]
          .get("expression");
        const type = path.getTypeAnnotation();
        expect(t.isUnionTypeAnnotation(type)).toBeTruthy();
        expect(t.isStringTypeAnnotation(type.types[0])).toBeTruthy();
        expect(t.isNumberTypeAnnotation(type.types[1])).toBeTruthy();
      });
      it("should infer type of conditional expression", function() {
        const path = getPath("q ? true : 0")
          .get("body")[0]
          .get("expression");
        const type = path.getTypeAnnotation();
        expect(t.isUnionTypeAnnotation(type)).toBeTruthy();
        expect(t.isBooleanTypeAnnotation(type.types[0])).toBeTruthy();
        expect(t.isNumberTypeAnnotation(type.types[1])).toBeTruthy();
      });
      it("should infer RegExp from RegExp literal", function() {
        const path = getPath("/.+/")
          .get("body")[0]
          .get("expression");
        const type = path.getTypeAnnotation();
        expect(
          t.isGenericTypeAnnotation(type) && type.id.name === "RegExp",
        ).toBeTruthy();
      });
      it("should infer Object from object expression", function() {
        const path = getPath("({ a: 5 })")
          .get("body")[0]
          .get("expression");
        const type = path.getTypeAnnotation();
        expect(
          t.isGenericTypeAnnotation(type) && type.id.name === "Object",
        ).toBeTruthy();
      });
      it("should infer Array from array expression", function() {
        const path = getPath("[ 5 ]")
          .get("body")[0]
          .get("expression");
        const type = path.getTypeAnnotation();
        expect(
          t.isGenericTypeAnnotation(type) && type.id.name === "Array",
        ).toBeTruthy();
      });
      it("should infer Function from function", function() {
        const path = getPath("(function (): string {})")
          .get("body")[0]
          .get("expression");
        const type = path.getTypeAnnotation();
        expect(
          t.isGenericTypeAnnotation(type) && type.id.name === "Function",
        ).toBeTruthy();
      });
      it("should infer call return type using function", function() {
        const path = getPath("(function (): string {})()")
          .get("body")[0]
          .get("expression");
        const type = path.getTypeAnnotation();
        expect(t.isStringTypeAnnotation(type)).toBeTruthy();
      });
      it("should infer call return type using async function", function() {
        const path = getPath("(async function (): string {})()")
          .get("body")[0]
          .get("expression");
        const type = path.getTypeAnnotation();
        expect(
          t.isGenericTypeAnnotation(type) && type.id.name === "Promise",
        ).toBeTruthy();
      });
      it("should infer call return type using async generator function", function() {
        const path = getPath("(async function * (): string {})()")
          .get("body")[0]
          .get("expression");
        const type = path.getTypeAnnotation();
        expect(
          t.isGenericTypeAnnotation(type) && type.id.name === "AsyncIterator",
        ).toBeTruthy();
      });
      it("should infer number from x/y", function() {
        const path = getPath("x/y")
          .get("body")[0]
          .get("expression");
        const type = path.getTypeAnnotation();
        expect(t.isNumberTypeAnnotation(type)).toBeTruthy();
      });
      it("should infer boolean from x instanceof y", function() {
        const path = getPath("x instanceof y")
          .get("body")[0]
          .get("expression");
        const type = path.getTypeAnnotation();
        expect(t.isBooleanTypeAnnotation(type)).toBeTruthy();
      });
      it("should infer number from 1 + 2", function() {
        const path = getPath("1 + 2")
          .get("body")[0]
          .get("expression");
        const type = path.getTypeAnnotation();
        expect(t.isNumberTypeAnnotation(type)).toBeTruthy();
      });
      it("should infer string|number from x + y", function() {
        const path = getPath("x + y")
          .get("body")[0]
          .get("expression");
        const type = path.getTypeAnnotation();
        expect(t.isUnionTypeAnnotation(type)).toBeTruthy();
        expect(t.isStringTypeAnnotation(type.types[0])).toBeTruthy();
        expect(t.isNumberTypeAnnotation(type.types[1])).toBeTruthy();
      });
      it("should infer type of tagged template literal", function() {
        const path = getPath("(function (): RegExp {}) `hey`")
          .get("body")[0]
          .get("expression");
        const type = path.getTypeAnnotation();
        expect(
          t.isGenericTypeAnnotation(type) && type.id.name === "RegExp",
        ).toBeTruthy();
      });
      it("should infer constant identifier", function() {
        const path = getPath("const x = 0; x").get("body.1.expression");
        const type = path.getTypeAnnotation();
        expect(t.isNumberTypeAnnotation(type)).toBeTruthy();
      });
      it("should infer indirect constant identifier", function() {
        const path = getPath("const x = 0; const y = x; y").get(
          "body.2.expression",
        );
        const type = path.getTypeAnnotation();
        expect(t.isNumberTypeAnnotation(type)).toBeTruthy();
      });
      it("should infer identifier type from if statement (===)", function() {
        const path = getPath(
          `function test(x) {
          if (x === true) x;
        }`,
        ).get("body.0.body.body.0.consequent.expression");
        const type = path.getTypeAnnotation();
        expect(t.isBooleanTypeAnnotation(type)).toBeTruthy();
      });
      it("should infer identifier type from if statement (typeof)", function() {
        let path = getPath(
          `function test(x) {
          if (typeof x == 'string') x;
        }`,
        ).get("body.0.body.body.0.consequent.expression");
        let type = path.getTypeAnnotation();
        expect(t.isStringTypeAnnotation(type)).toBeTruthy();
        path = getPath(
          `function test(x) {
          if (typeof x === 'number') x;
        }`,
        ).get("body.0.body.body.0.consequent.expression");
        type = path.getTypeAnnotation();
        expect(t.isNumberTypeAnnotation(type)).toBeTruthy();
      });
      it("should infer identifier type from if statement (&&)", function() {
        let path = getPath(
          `function test(x) {
          if (typeof x == 'string' && x === 3) x;
        }`,
        ).get("body.0.body.body.0.consequent.expression");
        let type = path.getTypeAnnotation();
        expect(t.isUnionTypeAnnotation(type)).toBeTruthy();
        expect(t.isStringTypeAnnotation(type.types[0])).toBeTruthy();
        expect(t.isNumberTypeAnnotation(type.types[1])).toBeTruthy();
        path = getPath(
          `function test(x) {
          if (true && x === 3) x;
        }`,
        ).get("body.0.body.body.0.consequent.expression");
        type = path.getTypeAnnotation();
        expect(t.isNumberTypeAnnotation(type)).toBeTruthy();
        path = getPath(
          `function test(x) {
          if (x === 'test' && true) x;
        }`,
        ).get("body.0.body.body.0.consequent.expression");
        type = path.getTypeAnnotation();
        expect(t.isStringTypeAnnotation(type)).toBeTruthy();
      });
      it("should infer identifier type from if statement (||)", function() {
        const path = getPath(
          `function test(x) {
          if (typeof x == 'string' || x === 3) x;
        }`,
        ).get("body.0.body.body.0.consequent.expression");
        const type = path.getTypeAnnotation();
        expect(t.isAnyTypeAnnotation(type)).toBeTruthy();
      });
      it("should not infer identifier type from incorrect binding", function() {
        const path = getPath(
          `function outer(x) {
          if (x === 3) {
            function inner(x) {
              x;
            }
          }
        }`,
        ).get("body.0.body.body.0.consequent.body.0.body.body.0.expression");
        const type = path.getTypeAnnotation();
        expect(t.isAnyTypeAnnotation(type)).toBeTruthy();
      });
    });
  });
  