@linaria/utils/esm/__tests__/removeDangerousCode.test.js

Blazing fast zero-runtime CSS in JS library

import { parseSync } from '@babel/core';
import generate from '@babel/generator';
import traverse from '@babel/traverse';
import dedent from 'dedent';
import { removeDangerousCode } from '../removeDangerousCode';
const run = code => {
  const ast = parseSync(dedent(code), {
    filename: 'test.tsx',
    presets: ['@babel/preset-typescript', '@babel/preset-react']
  });
  if (!ast) {
    throw new Error('Failed to parse');
  }
  traverse(ast, {
    Program(path) {
      removeDangerousCode(path);
    }
  });
  return generate(ast).code;
};
describe('removeDangerousCode', () => {
  it('should be defined', () => {
    expect(removeDangerousCode).toBeDefined();
  });
  it('should remove `window` but keep `setVersion` function untouched', () => {
    const result = run`
      let _win = undefined;

      try {
        _win = window;
      } catch (e) {
        /* no-op */
      }
      export function setVersion(packageName, packageVersion) {
        if (typeof _win !== 'undefined') {
          return null;
        }
      }
    `;
    expect(result).toMatchSnapshot();
  });
  it('should replace body of react component with null', () => {
    const result = run`
      export var Popup = /*#__PURE__*/function () {
        var Popup = function Popup() {
          var name = Popup.displayName;
          return <div>{name}</div>;
        };

        Popup.displayName = 'Popup';

        return Popup;
      }();
    `;
    expect(result).toMatchSnapshot();
  });
  it('should simplify ternary operator', () => {
    expect(run`
      export function getHostname(opts) {
        return typeof location !== "undefined" ? location.hostname : "localhost";
      }
    `).toMatchSnapshot();
    expect(run`
      export function getHostname(opts) {
        return location.hostname ? "location.hostname" : "localhost";
      }
    `).toMatchSnapshot();
    expect(run`
      export function getHostname(opts) {
        return opts ? "localhost" : location.hostname;
      }
    `).toMatchSnapshot();
    expect(run`
      export function getHostname(opts) {
        return opts ? location.hostname : "localhost";
      }
    `).toMatchSnapshot();
  });
  it('should simplify OR expression', () => {
    const result = run`
      export function getHostname(opts) {
        return opts.hostname || location.hostname;
      }
    `;
    expect(result).toMatchSnapshot();
  });
  it('should remove code under is-it-browser checks', () => {
    const result = run`
      let method;

      if (typeof window !== 'undefined') {
        console.log('it is browser');
        method = window.fetch;
      }

      if (typeof window === 'undefined') {
        console.log('it is not browser');
        method = fetch;
      }

      export function testFn(arg) {
        method(arg);
      }
    `;
    expect(result).toMatchSnapshot();
  });
  it('should simplify if statement', () => {
    const result = run`
      if (typeof window !== 'undefined') {
        console.log('it is browser');
      }

      if (typeof window === 'undefined') {
        console.log('it is not browser');
      }

      if (typeof window === 'undefined') {
        console.log('it is not browser');
      } else {
        console.log('it is browser');
      }

      if (typeof window !== 'undefined') {
        console.log('it is browser');
      } else {
        console.log('it is not browser');
      }
    `;
    expect(result).toMatchSnapshot();
  });
  it('should not remove class', () => {
    const result = run`
      class Test {
        constructor() {
          window.fetch();
        }
      }
    `;
    expect(result).toMatchSnapshot();
  });
});
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